These are all code cleanup changes.

Vast majority: Fixing unqualified access to class members (by adding
"this.").

A few cases of: Removing redundant generic attributes.
diff --git a/src/main/java/org/apache/datasketches/hive/cpc/DataToSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/cpc/DataToSketchUDAF.java
index 400d2bb..a9d44a0 100644
--- a/src/main/java/org/apache/datasketches/hive/cpc/DataToSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/cpc/DataToSketchUDAF.java
@@ -124,7 +124,7 @@
     public AggregationBuffer getNewAggregationBuffer() throws HiveException {
       // Different State is used for the iterate phase and the merge phase.
       // SketchState is more space-efficient, so let's use SketchState if possible.
-      if (mode_ == Mode.PARTIAL1 || mode_ == Mode.COMPLETE) { // iterate() will be used
+      if (this.mode_ == Mode.PARTIAL1 || this.mode_ == Mode.COMPLETE) { // iterate() will be used
         return new SketchState();
       }
       return new UnionState();
@@ -141,19 +141,19 @@
     @Override
     public ObjectInspector init(final Mode mode, final ObjectInspector[] parameters) throws HiveException {
       super.init(mode, parameters);
-      mode_ = mode;
+      this.mode_ = mode;
       if (mode == Mode.PARTIAL1 || mode == Mode.COMPLETE) {
         // input is original data
-        inputInspector_ = (PrimitiveObjectInspector) parameters[0];
+        this.inputInspector_ = (PrimitiveObjectInspector) parameters[0];
         if (parameters.length > 1) {
-          lgKInspector_ = (PrimitiveObjectInspector) parameters[1];
+          this.lgKInspector_ = (PrimitiveObjectInspector) parameters[1];
         }
         if (parameters.length > 2) {
-          seedInspector_ = (PrimitiveObjectInspector) parameters[2];
+          this.seedInspector_ = (PrimitiveObjectInspector) parameters[2];
         }
       } else {
         // input for PARTIAL2 and FINAL is the output from PARTIAL1
-        intermediateInspector_ = (StructObjectInspector) parameters[0];
+        this.intermediateInspector_ = (StructObjectInspector) parameters[0];
       }
 
       if (mode == Mode.PARTIAL1 || mode == Mode.PARTIAL2) {
@@ -181,24 +181,25 @@
      * java.lang.Object[])
      */
     @Override
-    public void iterate(final @SuppressWarnings("deprecation") AggregationBuffer agg,
+    @SuppressWarnings("deprecation")
+    public void iterate(final AggregationBuffer agg,
         final Object[] parameters) throws HiveException {
       if (parameters[0] == null) { return; }
       final SketchState state = (SketchState) agg;
       if (!state.isInitialized()) {
         initializeState(state, parameters);
       }
-      state.update(parameters[0], inputInspector_);
+      state.update(parameters[0], this.inputInspector_);
     }
 
     private void initializeState(final State state, final Object[] parameters) {
       int lgK = DEFAULT_LG_K;
-      if (lgKInspector_ != null) {
-        lgK = PrimitiveObjectInspectorUtils.getInt(parameters[1], lgKInspector_);
+      if (this.lgKInspector_ != null) {
+        lgK = PrimitiveObjectInspectorUtils.getInt(parameters[1], this.lgKInspector_);
       }
       long seed = DEFAULT_UPDATE_SEED;
-      if (seedInspector_ != null) {
-        seed = PrimitiveObjectInspectorUtils.getLong(parameters[2], seedInspector_);
+      if (this.seedInspector_ != null) {
+        seed = PrimitiveObjectInspectorUtils.getLong(parameters[2], this.seedInspector_);
       }
       state.init(lgK, seed);
     }
diff --git a/src/main/java/org/apache/datasketches/hive/cpc/SketchEvaluator.java b/src/main/java/org/apache/datasketches/hive/cpc/SketchEvaluator.java
index ca2e0a9..b07505e 100644
--- a/src/main/java/org/apache/datasketches/hive/cpc/SketchEvaluator.java
+++ b/src/main/java/org/apache/datasketches/hive/cpc/SketchEvaluator.java
@@ -61,23 +61,24 @@
   }
 
   @Override
-  public void merge(final @SuppressWarnings("deprecation") AggregationBuffer buf, final Object data)
+  @SuppressWarnings("deprecation")
+  public void merge(final AggregationBuffer buf, final Object data)
       throws HiveException {
     if (data == null) { return; }
     final UnionState state = (UnionState) buf;
     if (!state.isInitialized()) {
       initializeState(state, data);
     }
-    final BytesWritable serializedSketch = (BytesWritable) intermediateInspector_.getStructFieldData(
-        data, intermediateInspector_.getStructFieldRef(SKETCH_FIELD));
+    final BytesWritable serializedSketch = (BytesWritable) this.intermediateInspector_.getStructFieldData(
+        data, this.intermediateInspector_.getStructFieldRef(SKETCH_FIELD));
     state.update(CpcSketch.heapify(BytesWritableHelper.wrapAsMemory(serializedSketch), state.getSeed()));
   }
 
   private void initializeState(final UnionState state, final Object data) {
-    final int lgK = ((IntWritable) intermediateInspector_.getStructFieldData(
-        data, intermediateInspector_.getStructFieldRef(LG_K_FIELD))).get();
-    final long seed = ((LongWritable) intermediateInspector_.getStructFieldData(
-        data, intermediateInspector_.getStructFieldRef(SEED_FIELD))).get();
+    final int lgK = ((IntWritable) this.intermediateInspector_.getStructFieldData(
+        data, this.intermediateInspector_.getStructFieldRef(LG_K_FIELD))).get();
+    final long seed = ((LongWritable) this.intermediateInspector_.getStructFieldData(
+        data, this.intermediateInspector_.getStructFieldRef(SEED_FIELD))).get();
     state.init(lgK, seed);
   }
 
diff --git a/src/main/java/org/apache/datasketches/hive/cpc/SketchState.java b/src/main/java/org/apache/datasketches/hive/cpc/SketchState.java
index 5206fe7..37911cc 100644
--- a/src/main/java/org/apache/datasketches/hive/cpc/SketchState.java
+++ b/src/main/java/org/apache/datasketches/hive/cpc/SketchState.java
@@ -29,47 +29,47 @@
 
   @Override
   boolean isInitialized() {
-    return sketch_ != null;
+    return this.sketch_ != null;
   }
 
   @Override
   void init(final int logK, final long seed) {
     super.init(logK, seed);
-    sketch_ = new CpcSketch(logK, seed);
+    this.sketch_ = new CpcSketch(logK, seed);
   }
 
   void update(final Object data, final PrimitiveObjectInspector objectInspector) {
     switch (objectInspector.getPrimitiveCategory()) {
       case BINARY:
-        sketch_.update(PrimitiveObjectInspectorUtils.getBinary(data, objectInspector)
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getBinary(data, objectInspector)
             .copyBytes());
         return;
       case BYTE:
-        sketch_.update(PrimitiveObjectInspectorUtils.getByte(data, objectInspector));
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getByte(data, objectInspector));
         return;
       case DOUBLE:
-        sketch_.update(PrimitiveObjectInspectorUtils.getDouble(data, objectInspector));
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getDouble(data, objectInspector));
         return;
       case FLOAT:
-        sketch_.update(PrimitiveObjectInspectorUtils.getFloat(data, objectInspector));
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getFloat(data, objectInspector));
         return;
       case INT:
-        sketch_.update(PrimitiveObjectInspectorUtils.getInt(data, objectInspector));
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getInt(data, objectInspector));
         return;
       case LONG:
-        sketch_.update(PrimitiveObjectInspectorUtils.getLong(data, objectInspector));
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getLong(data, objectInspector));
         return;
       case STRING:
         // conversion to char[] avoids costly UTF-8 encoding
-        sketch_.update(PrimitiveObjectInspectorUtils.getString(data, objectInspector)
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getString(data, objectInspector)
             .toCharArray());
         return;
       case CHAR:
-        sketch_.update(PrimitiveObjectInspectorUtils.getHiveChar(data, objectInspector)
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getHiveChar(data, objectInspector)
             .getValue().toCharArray());
         return;
       case VARCHAR:
-        sketch_.update(PrimitiveObjectInspectorUtils.getHiveVarchar(data, objectInspector)
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getHiveVarchar(data, objectInspector)
             .getValue().toCharArray());
         return;
       default:
@@ -82,13 +82,13 @@
 
   @Override
   CpcSketch getResult() {
-    if (sketch_ == null) { return null; }
-    return sketch_;
+    if (this.sketch_ == null) { return null; }
+    return this.sketch_;
   }
 
   @Override
   void reset() {
-    sketch_ = null;
+    this.sketch_ = null;
   }
 
 }
diff --git a/src/main/java/org/apache/datasketches/hive/cpc/State.java b/src/main/java/org/apache/datasketches/hive/cpc/State.java
index f3b9e1e..c9bcaee 100644
--- a/src/main/java/org/apache/datasketches/hive/cpc/State.java
+++ b/src/main/java/org/apache/datasketches/hive/cpc/State.java
@@ -28,16 +28,16 @@
   private long seed_;
 
   void init(final int lgK, final long seed) {
-    lgK_ = lgK;
-    seed_ = seed;
+    this.lgK_ = lgK;
+    this.seed_ = seed;
   }
 
   int getLgK() {
-    return lgK_;
+    return this.lgK_;
   }
 
   long getSeed() {
-    return seed_;
+    return this.seed_;
   }
 
   abstract boolean isInitialized();
diff --git a/src/main/java/org/apache/datasketches/hive/cpc/UnionSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/cpc/UnionSketchUDAF.java
index 7e22c3d..726ceb8 100644
--- a/src/main/java/org/apache/datasketches/hive/cpc/UnionSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/cpc/UnionSketchUDAF.java
@@ -130,16 +130,16 @@
       super.init(mode, parameters);
 
       if ((mode == Mode.PARTIAL1) || (mode == Mode.COMPLETE)) {
-        inputInspector_ = (PrimitiveObjectInspector) parameters[0];
+        this.inputInspector_ = (PrimitiveObjectInspector) parameters[0];
         if (parameters.length > 1) {
-          lgKInspector_ = (PrimitiveObjectInspector) parameters[1];
+          this.lgKInspector_ = (PrimitiveObjectInspector) parameters[1];
         }
         if (parameters.length > 2) {
-          seedInspector_ = (PrimitiveObjectInspector) parameters[2];
+          this.seedInspector_ = (PrimitiveObjectInspector) parameters[2];
         }
       } else {
         // mode = partial2 || final
-        intermediateInspector_ = (StandardStructObjectInspector) parameters[0];
+        this.intermediateInspector_ = (StandardStructObjectInspector) parameters[0];
       }
 
       if ((mode == Mode.PARTIAL1) || (mode == Mode.PARTIAL2)) {
@@ -173,19 +173,19 @@
       if (!state.isInitialized()) {
         initializeState(state, parameters);
       }
-      final byte[] serializedSketch = (byte[]) inputInspector_.getPrimitiveJavaObject(parameters[0]);
+      final byte[] serializedSketch = (byte[]) this.inputInspector_.getPrimitiveJavaObject(parameters[0]);
       if (serializedSketch == null) { return; }
       state.update(CpcSketch.heapify(Memory.wrap(serializedSketch), state.getSeed()));
     }
 
     private void initializeState(final UnionState state, final Object[] parameters) {
       int lgK = DEFAULT_LG_K;
-      if (lgKInspector_ != null) {
-        lgK = PrimitiveObjectInspectorUtils.getInt(parameters[1], lgKInspector_);
+      if (this.lgKInspector_ != null) {
+        lgK = PrimitiveObjectInspectorUtils.getInt(parameters[1], this.lgKInspector_);
       }
       long seed = DEFAULT_UPDATE_SEED;
-      if (seedInspector_ != null) {
-        seed = PrimitiveObjectInspectorUtils.getLong(parameters[2], seedInspector_);
+      if (this.seedInspector_ != null) {
+        seed = PrimitiveObjectInspectorUtils.getLong(parameters[2], this.seedInspector_);
       }
       state.init(lgK, seed);
     }
diff --git a/src/main/java/org/apache/datasketches/hive/cpc/UnionState.java b/src/main/java/org/apache/datasketches/hive/cpc/UnionState.java
index 4ca1006..5fe0b67 100644
--- a/src/main/java/org/apache/datasketches/hive/cpc/UnionState.java
+++ b/src/main/java/org/apache/datasketches/hive/cpc/UnionState.java
@@ -28,28 +28,28 @@
 
   @Override
   boolean isInitialized() {
-    return union_ != null;
+    return this.union_ != null;
   }
 
   @Override
   void init(final int lgK, final long seed) {
     super.init(lgK, seed);
-    union_ = new CpcUnion(lgK, seed);
+    this.union_ = new CpcUnion(lgK, seed);
   }
 
   void update(final CpcSketch sketch) {
-    union_.update(sketch);
+    this.union_.update(sketch);
   }
 
   @Override
   CpcSketch getResult() {
-    if (union_ == null) { return null; }
-    return union_.getResult();
+    if (this.union_ == null) { return null; }
+    return this.union_.getResult();
   }
 
   @Override
   void reset() {
-    union_ = null;
+    this.union_ = null;
   }
 
 }
diff --git a/src/main/java/org/apache/datasketches/hive/frequencies/DataToItemsSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/frequencies/DataToItemsSketchUDAF.java
index 93da5d6..714f59b 100644
--- a/src/main/java/org/apache/datasketches/hive/frequencies/DataToItemsSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/frequencies/DataToItemsSketchUDAF.java
@@ -84,7 +84,7 @@
       // In PARTIAL2 and FINAL mode, the parameters are just partial aggregations.
       if ((mode == Mode.PARTIAL1) || (mode == Mode.COMPLETE)) {
         if (parameters.length > 1) {
-          maxMapSizeObjectInspector = (PrimitiveObjectInspector) parameters[1];
+          this.maxMapSizeObjectInspector = (PrimitiveObjectInspector) parameters[1];
         }
       }
 
@@ -98,10 +98,10 @@
       @SuppressWarnings("unchecked")
       final ItemsState<T> state = (ItemsState<T>) buf;
       if (!state.isInitialized()) {
-        final int maxMapSize = PrimitiveObjectInspectorUtils.getInt(data[1], maxMapSizeObjectInspector);
+        final int maxMapSize = PrimitiveObjectInspectorUtils.getInt(data[1], this.maxMapSizeObjectInspector);
         state.init(maxMapSize);
       }
-      state.update(extractValue(data[0], inputObjectInspector));
+      state.update(extractValue(data[0], this.inputObjectInspector));
     }
 
     public abstract T extractValue(final Object data, final ObjectInspector objectInspector)
diff --git a/src/main/java/org/apache/datasketches/hive/frequencies/DataToStringsSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/frequencies/DataToStringsSketchUDAF.java
index 39d8303..1c87f2d 100644
--- a/src/main/java/org/apache/datasketches/hive/frequencies/DataToStringsSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/frequencies/DataToStringsSketchUDAF.java
@@ -49,7 +49,7 @@
     @Override
     public String extractValue(final Object data, final ObjectInspector objectInspector)
         throws HiveException {
-      final Object value = inputObjectInspector.getPrimitiveJavaObject(data);
+      final Object value = this.inputObjectInspector.getPrimitiveJavaObject(data);
       if (value instanceof String) {
         return (String) value;
       } else if (value instanceof HiveChar) {
diff --git a/src/main/java/org/apache/datasketches/hive/frequencies/GetFrequentItemsFromStringsSketchUDTF.java b/src/main/java/org/apache/datasketches/hive/frequencies/GetFrequentItemsFromStringsSketchUDTF.java
index 25a4021..218bf74 100644
--- a/src/main/java/org/apache/datasketches/hive/frequencies/GetFrequentItemsFromStringsSketchUDTF.java
+++ b/src/main/java/org/apache/datasketches/hive/frequencies/GetFrequentItemsFromStringsSketchUDTF.java
@@ -58,10 +58,10 @@
       throw new UDFArgumentTypeException(0, "Primitive argument expected, but "
           + inspectors[0].getCategory().name() + " was recieved");
     }
-    inputObjectInspector = (PrimitiveObjectInspector) inspectors[0];
-    if (inputObjectInspector.getPrimitiveCategory() != PrimitiveObjectInspector.PrimitiveCategory.BINARY) {
+    this.inputObjectInspector = (PrimitiveObjectInspector) inspectors[0];
+    if (this.inputObjectInspector.getPrimitiveCategory() != PrimitiveObjectInspector.PrimitiveCategory.BINARY) {
       throw new UDFArgumentTypeException(0, "Binary value expected as the first argument, but "
-          + inputObjectInspector.getPrimitiveCategory().name() + " was recieved");
+          + this.inputObjectInspector.getPrimitiveCategory().name() + " was recieved");
     }
 
     if (inspectors.length > 1) {
@@ -69,11 +69,11 @@
         throw new UDFArgumentTypeException(1, "Primitive argument expected, but "
             + inspectors[1].getCategory().name() + " was recieved");
       }
-      errorTypeObjectInspector = (PrimitiveObjectInspector) inspectors[1];
-      if (errorTypeObjectInspector.getPrimitiveCategory()
+      this.errorTypeObjectInspector = (PrimitiveObjectInspector) inspectors[1];
+      if (this.errorTypeObjectInspector.getPrimitiveCategory()
           != PrimitiveObjectInspector.PrimitiveCategory.STRING) {
         throw new UDFArgumentTypeException(1, "String value expected as the first argument, but "
-            + errorTypeObjectInspector.getPrimitiveCategory().name() + " was recieved");
+            + this.errorTypeObjectInspector.getPrimitiveCategory().name() + " was recieved");
       }
     }
 
@@ -92,12 +92,12 @@
   public void process(final Object[] data) throws HiveException {
     if (data == null || data[0] == null) { return; }
     final BytesWritable serializedSketch =
-        (BytesWritable) inputObjectInspector.getPrimitiveWritableObject(data[0]);
+        (BytesWritable) this.inputObjectInspector.getPrimitiveWritableObject(data[0]);
     final ItemsSketch<String> sketch = ItemsSketch.getInstance(
         BytesWritableHelper.wrapAsMemory(serializedSketch), new ArrayOfStringsSerDe());
     ErrorType errorType = ErrorType.NO_FALSE_POSITIVES;
     if (data.length > 1) {
-      errorType = ErrorType.valueOf((String) errorTypeObjectInspector.getPrimitiveJavaObject(data[1]));
+      errorType = ErrorType.valueOf((String) this.errorTypeObjectInspector.getPrimitiveJavaObject(data[1]));
     }
     final ItemsSketch.Row<String>[] result = sketch.getFrequentItems(errorType);
     for (int i = 0; i < result.length; i++) {
diff --git a/src/main/java/org/apache/datasketches/hive/frequencies/ItemsEvaluator.java b/src/main/java/org/apache/datasketches/hive/frequencies/ItemsEvaluator.java
index 4d5a629..c3154a4 100644
--- a/src/main/java/org/apache/datasketches/hive/frequencies/ItemsEvaluator.java
+++ b/src/main/java/org/apache/datasketches/hive/frequencies/ItemsEvaluator.java
@@ -37,13 +37,13 @@
   protected PrimitiveObjectInspector inputObjectInspector;
 
   ItemsEvaluator(final ArrayOfItemsSerDe<T> serDe) {
-    serDe_ = serDe;
+    this.serDe_ = serDe;
   }
 
   @Override
   public ObjectInspector init(final Mode mode, final ObjectInspector[] parameters) throws HiveException {
     super.init(mode, parameters);
-    inputObjectInspector = (PrimitiveObjectInspector) parameters[0];
+    this.inputObjectInspector = (PrimitiveObjectInspector) parameters[0];
     return PrimitiveObjectInspectorFactory.getPrimitiveWritableObjectInspector(PrimitiveCategory.BINARY);
   }
 
@@ -68,7 +68,7 @@
     @SuppressWarnings("unchecked")
     final ItemsState<T> state = (ItemsState<T>) buf;
     final Memory serializedSketch = BytesWritableHelper.wrapAsMemory(
-        (BytesWritable) inputObjectInspector.getPrimitiveWritableObject(data));
+        (BytesWritable) this.inputObjectInspector.getPrimitiveWritableObject(data));
     state.update(serializedSketch);
   }
 
@@ -79,13 +79,13 @@
     final ItemsState<T> state = (ItemsState<T>) buf;
     final ItemsSketch<T> resultSketch = state.getResult();
     if (resultSketch == null) { return null; }
-    return new BytesWritable(resultSketch.toByteArray(serDe_));
+    return new BytesWritable(resultSketch.toByteArray(this.serDe_));
   }
 
   @SuppressWarnings("deprecation")
   @Override
   public AggregationBuffer getNewAggregationBuffer() throws HiveException {
-    return new ItemsState<>(serDe_);
+    return new ItemsState<>(this.serDe_);
   }
 
 }
diff --git a/src/main/java/org/apache/datasketches/hive/frequencies/ItemsState.java b/src/main/java/org/apache/datasketches/hive/frequencies/ItemsState.java
index 09478c8..08d0243 100644
--- a/src/main/java/org/apache/datasketches/hive/frequencies/ItemsState.java
+++ b/src/main/java/org/apache/datasketches/hive/frequencies/ItemsState.java
@@ -31,39 +31,39 @@
   private ItemsSketch<T> sketch;
 
   ItemsState(final ArrayOfItemsSerDe<T> serDe) {
-    serDe_ = serDe;
+    this.serDe_ = serDe;
   }
 
   // initializing maxMapSize is needed for building sketches using update(value)
   // not needed for merging sketches using update(sketch)
   void init(final int maxMapSize) {
-    maxMapSize_ = maxMapSize;
-    sketch = new ItemsSketch<>(maxMapSize_);
+    this.maxMapSize_ = maxMapSize;
+    this.sketch = new ItemsSketch<>(this.maxMapSize_);
   }
 
   boolean isInitialized() {
-    return sketch != null;
+    return this.sketch != null;
   }
 
   void update(final T value) {
-    sketch.update(value);
+    this.sketch.update(value);
   }
 
   void update(final Memory serializedSketch) {
-    final ItemsSketch<T> incomingSketch = ItemsSketch.getInstance(serializedSketch, serDe_);
-    if (sketch == null) {
-      sketch = incomingSketch;
+    final ItemsSketch<T> incomingSketch = ItemsSketch.getInstance(serializedSketch, this.serDe_);
+    if (this.sketch == null) {
+      this.sketch = incomingSketch;
     } else {
-      sketch.merge(incomingSketch);
+      this.sketch.merge(incomingSketch);
     }
   }
 
   public ItemsSketch<T> getResult() {
-    return sketch;
+    return this.sketch;
   }
 
   void reset() {
-    sketch = null;
+    this.sketch = null;
   }
 
 }
diff --git a/src/main/java/org/apache/datasketches/hive/hll/DataToSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/hll/DataToSketchUDAF.java
index 0e05f93..e952eb1 100644
--- a/src/main/java/org/apache/datasketches/hive/hll/DataToSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/hll/DataToSketchUDAF.java
@@ -128,7 +128,7 @@
       // so the mode_ was null. A solution was implemented to have UnionState, which can work
       // in both cases, but SketchState is more space-efficient.
       // HLL sketch is about compactness, so let's use SketchState if possible.
-      if (mode_ == Mode.PARTIAL1 || mode_ == Mode.COMPLETE) { // iterate() will be used
+      if (this.mode_ == Mode.PARTIAL1 || this.mode_ == Mode.COMPLETE) { // iterate() will be used
         return new SketchState();
       }
       return new UnionState();
@@ -145,19 +145,19 @@
     @Override
     public ObjectInspector init(final Mode mode, final ObjectInspector[] parameters) throws HiveException {
       super.init(mode, parameters);
-      mode_ = mode;
+      this.mode_ = mode;
       if (mode == Mode.PARTIAL1 || mode == Mode.COMPLETE) {
         // input is original data
-        inputInspector_ = (PrimitiveObjectInspector) parameters[0];
+        this.inputInspector_ = (PrimitiveObjectInspector) parameters[0];
         if (parameters.length > 1) {
-          lgKInspector_ = (PrimitiveObjectInspector) parameters[1];
+          this.lgKInspector_ = (PrimitiveObjectInspector) parameters[1];
         }
         if (parameters.length > 2) {
-          hllTypeInspector_ = (PrimitiveObjectInspector) parameters[2];
+          this.hllTypeInspector_ = (PrimitiveObjectInspector) parameters[2];
         }
       } else {
         // input for PARTIAL2 and FINAL is the output from PARTIAL1
-        intermediateInspector_ = (StructObjectInspector) parameters[0];
+        this.intermediateInspector_ = (StructObjectInspector) parameters[0];
       }
 
       if (mode == Mode.PARTIAL1 || mode == Mode.PARTIAL2) {
@@ -192,17 +192,17 @@
       if (!state.isInitialized()) {
         initializeState(state, parameters);
       }
-      state.update(parameters[0], inputInspector_);
+      state.update(parameters[0], this.inputInspector_);
     }
 
     private void initializeState(final State state, final Object[] parameters) {
       int lgK = DEFAULT_LG_K;
-      if (lgKInspector_ != null) {
-        lgK = PrimitiveObjectInspectorUtils.getInt(parameters[1], lgKInspector_);
+      if (this.lgKInspector_ != null) {
+        lgK = PrimitiveObjectInspectorUtils.getInt(parameters[1], this.lgKInspector_);
       }
       TgtHllType type = DEFAULT_HLL_TYPE;
-      if (hllTypeInspector_ != null) {
-        type = TgtHllType.valueOf(PrimitiveObjectInspectorUtils.getString(parameters[2], hllTypeInspector_));
+      if (this.hllTypeInspector_ != null) {
+        type = TgtHllType.valueOf(PrimitiveObjectInspectorUtils.getString(parameters[2], this.hllTypeInspector_));
       }
       state.init(lgK, type);
     }
diff --git a/src/main/java/org/apache/datasketches/hive/hll/SketchEvaluator.java b/src/main/java/org/apache/datasketches/hive/hll/SketchEvaluator.java
index 083f9ac..3cb63b9 100644
--- a/src/main/java/org/apache/datasketches/hive/hll/SketchEvaluator.java
+++ b/src/main/java/org/apache/datasketches/hive/hll/SketchEvaluator.java
@@ -70,16 +70,16 @@
     if (!state.isInitialized()) {
       initializeState(state, data);
     }
-    final BytesWritable serializedSketch = (BytesWritable) intermediateInspector_.getStructFieldData(
-        data, intermediateInspector_.getStructFieldRef(SKETCH_FIELD));
+    final BytesWritable serializedSketch = (BytesWritable) this.intermediateInspector_.getStructFieldData(
+        data, this.intermediateInspector_.getStructFieldRef(SKETCH_FIELD));
     state.update(HllSketch.wrap(BytesWritableHelper.wrapAsMemory(serializedSketch)));
   }
 
   private void initializeState(final UnionState state, final Object data) {
-    final int lgK = ((IntWritable) intermediateInspector_.getStructFieldData(
-        data, intermediateInspector_.getStructFieldRef(LG_K_FIELD))).get();
-    final TgtHllType type = TgtHllType.valueOf(((Text) intermediateInspector_.getStructFieldData(
-        data, intermediateInspector_.getStructFieldRef(HLL_TYPE_FIELD))).toString());
+    final int lgK = ((IntWritable) this.intermediateInspector_.getStructFieldData(
+        data, this.intermediateInspector_.getStructFieldRef(LG_K_FIELD))).get();
+    final TgtHllType type = TgtHllType.valueOf(((Text) this.intermediateInspector_.getStructFieldData(
+        data, this.intermediateInspector_.getStructFieldRef(HLL_TYPE_FIELD))).toString());
     state.init(lgK, type);
   }
 
diff --git a/src/main/java/org/apache/datasketches/hive/hll/SketchState.java b/src/main/java/org/apache/datasketches/hive/hll/SketchState.java
index c002a47..8cf58d6 100644
--- a/src/main/java/org/apache/datasketches/hive/hll/SketchState.java
+++ b/src/main/java/org/apache/datasketches/hive/hll/SketchState.java
@@ -30,48 +30,48 @@
 
   @Override
   boolean isInitialized() {
-    return sketch_ != null;
+    return this.sketch_ != null;
   }
 
   @Override
   void init(final int logK, final TgtHllType type) {
     super.init(logK, type);
-    sketch_ = new HllSketch(logK, type);
+    this.sketch_ = new HllSketch(logK, type);
   }
 
   @Override
   void update(final Object data, final PrimitiveObjectInspector objectInspector) {
     switch (objectInspector.getPrimitiveCategory()) {
       case BINARY:
-        sketch_.update(PrimitiveObjectInspectorUtils.getBinary(data, objectInspector)
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getBinary(data, objectInspector)
             .copyBytes());
         return;
       case BYTE:
-        sketch_.update(PrimitiveObjectInspectorUtils.getByte(data, objectInspector));
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getByte(data, objectInspector));
         return;
       case DOUBLE:
-        sketch_.update(PrimitiveObjectInspectorUtils.getDouble(data, objectInspector));
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getDouble(data, objectInspector));
         return;
       case FLOAT:
-        sketch_.update(PrimitiveObjectInspectorUtils.getFloat(data, objectInspector));
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getFloat(data, objectInspector));
         return;
       case INT:
-        sketch_.update(PrimitiveObjectInspectorUtils.getInt(data, objectInspector));
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getInt(data, objectInspector));
         return;
       case LONG:
-        sketch_.update(PrimitiveObjectInspectorUtils.getLong(data, objectInspector));
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getLong(data, objectInspector));
         return;
       case STRING:
         // conversion to char[] avoids costly UTF-8 encoding
-        sketch_.update(PrimitiveObjectInspectorUtils.getString(data, objectInspector)
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getString(data, objectInspector)
             .toCharArray());
         return;
       case CHAR:
-        sketch_.update(PrimitiveObjectInspectorUtils.getHiveChar(data, objectInspector)
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getHiveChar(data, objectInspector)
             .getValue().toCharArray());
         return;
       case VARCHAR:
-        sketch_.update(PrimitiveObjectInspectorUtils.getHiveVarchar(data, objectInspector)
+        this.sketch_.update(PrimitiveObjectInspectorUtils.getHiveVarchar(data, objectInspector)
             .getValue().toCharArray());
         return;
       default:
@@ -84,13 +84,13 @@
 
   @Override
   HllSketch getResult() {
-    if (sketch_ == null) { return null; }
-    return sketch_;
+    if (this.sketch_ == null) { return null; }
+    return this.sketch_;
   }
 
   @Override
   void reset() {
-    sketch_ = null;
+    this.sketch_ = null;
   }
 
 }
diff --git a/src/main/java/org/apache/datasketches/hive/hll/State.java b/src/main/java/org/apache/datasketches/hive/hll/State.java
index fa9e5df..c6e43ca 100644
--- a/src/main/java/org/apache/datasketches/hive/hll/State.java
+++ b/src/main/java/org/apache/datasketches/hive/hll/State.java
@@ -30,16 +30,16 @@
   private TgtHllType type_;
 
   void init(final int lgK, final TgtHllType type) {
-    lgK_ = lgK;
-    type_ = type;
+    this.lgK_ = lgK;
+    this.type_ = type;
   }
 
   int getLgK() {
-    return lgK_;
+    return this.lgK_;
   }
 
   TgtHllType getType() {
-    return type_;
+    return this.type_;
   }
 
   abstract boolean isInitialized();
diff --git a/src/main/java/org/apache/datasketches/hive/hll/UnionSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/hll/UnionSketchUDAF.java
index 7563fc9..ac96c9f 100644
--- a/src/main/java/org/apache/datasketches/hive/hll/UnionSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/hll/UnionSketchUDAF.java
@@ -130,16 +130,16 @@
       super.init(mode, parameters);
 
       if (mode == Mode.PARTIAL1 || mode == Mode.COMPLETE) {
-        inputInspector_ = (PrimitiveObjectInspector) parameters[0];
+        this.inputInspector_ = (PrimitiveObjectInspector) parameters[0];
         if (parameters.length > 1) {
-          lgKInspector_ = (PrimitiveObjectInspector) parameters[1];
+          this.lgKInspector_ = (PrimitiveObjectInspector) parameters[1];
         }
         if (parameters.length > 2) {
-          hllTypeInspector_ = (PrimitiveObjectInspector) parameters[2];
+          this.hllTypeInspector_ = (PrimitiveObjectInspector) parameters[2];
         }
       } else {
         // mode = partial2 || final
-        intermediateInspector_ = (StandardStructObjectInspector) parameters[0];
+        this.intermediateInspector_ = (StandardStructObjectInspector) parameters[0];
       }
 
       if (mode == Mode.PARTIAL1 || mode == Mode.PARTIAL2) {
@@ -173,19 +173,19 @@
       if (!state.isInitialized()) {
         initializeState(state, parameters);
       }
-      final byte[] serializedSketch = (byte[]) inputInspector_.getPrimitiveJavaObject(parameters[0]);
+      final byte[] serializedSketch = (byte[]) this.inputInspector_.getPrimitiveJavaObject(parameters[0]);
       if (serializedSketch == null) { return; }
       state.update(HllSketch.wrap(Memory.wrap(serializedSketch)));
     }
 
     private void initializeState(final UnionState state, final Object[] parameters) {
       int lgK = DEFAULT_LG_K;
-      if (lgKInspector_ != null) {
-        lgK = PrimitiveObjectInspectorUtils.getInt(parameters[1], lgKInspector_);
+      if (this.lgKInspector_ != null) {
+        lgK = PrimitiveObjectInspectorUtils.getInt(parameters[1], this.lgKInspector_);
       }
       TgtHllType type = DEFAULT_HLL_TYPE;
-      if (hllTypeInspector_ != null) {
-        type = TgtHllType.valueOf(PrimitiveObjectInspectorUtils.getString(parameters[2], hllTypeInspector_));
+      if (this.hllTypeInspector_ != null) {
+        type = TgtHllType.valueOf(PrimitiveObjectInspectorUtils.getString(parameters[2], this.hllTypeInspector_));
       }
       state.init(lgK, type);
     }
diff --git a/src/main/java/org/apache/datasketches/hive/hll/UnionState.java b/src/main/java/org/apache/datasketches/hive/hll/UnionState.java
index 89d8e06..42ff126 100644
--- a/src/main/java/org/apache/datasketches/hive/hll/UnionState.java
+++ b/src/main/java/org/apache/datasketches/hive/hll/UnionState.java
@@ -31,48 +31,48 @@
 
   @Override
   boolean isInitialized() {
-    return union_ != null;
+    return this.union_ != null;
   }
 
   @Override
   void init(final int lgK, final TgtHllType type) {
     super.init(lgK, type);
-    union_ = new Union(lgK);
+    this.union_ = new Union(lgK);
   }
 
   @Override
   void update(final Object data, final PrimitiveObjectInspector objectInspector) {
     switch (objectInspector.getPrimitiveCategory()) {
       case BINARY:
-        union_.update(PrimitiveObjectInspectorUtils.getBinary(data, objectInspector)
+        this.union_.update(PrimitiveObjectInspectorUtils.getBinary(data, objectInspector)
             .copyBytes());
         return;
       case BYTE:
-        union_.update(PrimitiveObjectInspectorUtils.getByte(data, objectInspector));
+        this.union_.update(PrimitiveObjectInspectorUtils.getByte(data, objectInspector));
         return;
       case DOUBLE:
-        union_.update(PrimitiveObjectInspectorUtils.getDouble(data, objectInspector));
+        this.union_.update(PrimitiveObjectInspectorUtils.getDouble(data, objectInspector));
         return;
       case FLOAT:
-        union_.update(PrimitiveObjectInspectorUtils.getFloat(data, objectInspector));
+        this.union_.update(PrimitiveObjectInspectorUtils.getFloat(data, objectInspector));
         return;
       case INT:
-        union_.update(PrimitiveObjectInspectorUtils.getInt(data, objectInspector));
+        this.union_.update(PrimitiveObjectInspectorUtils.getInt(data, objectInspector));
         return;
       case LONG:
-        union_.update(PrimitiveObjectInspectorUtils.getLong(data, objectInspector));
+        this.union_.update(PrimitiveObjectInspectorUtils.getLong(data, objectInspector));
         return;
       case STRING:
         // conversion to char[] avoids costly UTF-8 encoding
-        union_.update(PrimitiveObjectInspectorUtils.getString(data, objectInspector)
+        this.union_.update(PrimitiveObjectInspectorUtils.getString(data, objectInspector)
             .toCharArray());
         return;
       case CHAR:
-        union_.update(PrimitiveObjectInspectorUtils.getHiveChar(data, objectInspector)
+        this.union_.update(PrimitiveObjectInspectorUtils.getHiveChar(data, objectInspector)
             .getValue().toCharArray());
         return;
       case VARCHAR:
-        union_.update(PrimitiveObjectInspectorUtils.getHiveVarchar(data, objectInspector)
+        this.union_.update(PrimitiveObjectInspectorUtils.getHiveVarchar(data, objectInspector)
             .getValue().toCharArray());
         return;
       default:
@@ -84,18 +84,18 @@
   }
 
   void update(final HllSketch sketch) {
-    union_.update(sketch);
+    this.union_.update(sketch);
   }
 
   @Override
   HllSketch getResult() {
-    if (union_ == null) { return null; }
-    return union_.getResult(getType());
+    if (this.union_ == null) { return null; }
+    return this.union_.getResult(getType());
   }
 
   @Override
   void reset() {
-    union_ = null;
+    this.union_ = null;
   }
 
 }
diff --git a/src/main/java/org/apache/datasketches/hive/kll/DataToSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/kll/DataToSketchUDAF.java
index f77db2a..bb7e2a5 100644
--- a/src/main/java/org/apache/datasketches/hive/kll/DataToSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/kll/DataToSketchUDAF.java
@@ -62,13 +62,13 @@
       if (data[0] == null) { return; }
       final SketchState state = (SketchState) buf;
       if (!state.isInitialized()) {
-        if (kInspector_ != null) {
-          state.init(PrimitiveObjectInspectorUtils.getInt(data[1], kInspector_));
+        if (this.kInspector_ != null) {
+          state.init(PrimitiveObjectInspectorUtils.getInt(data[1], this.kInspector_));
         } else {
           state.init();
         }
       }
-      final float value = (float) inputInspector_.getPrimitiveJavaObject(data[0]);
+      final float value = (float) this.inputInspector_.getPrimitiveJavaObject(data[0]);
       state.update(value);
     }
 
diff --git a/src/main/java/org/apache/datasketches/hive/kll/SketchEvaluator.java b/src/main/java/org/apache/datasketches/hive/kll/SketchEvaluator.java
index d5ec827..c71d88a 100644
--- a/src/main/java/org/apache/datasketches/hive/kll/SketchEvaluator.java
+++ b/src/main/java/org/apache/datasketches/hive/kll/SketchEvaluator.java
@@ -38,14 +38,14 @@
   @Override
   public ObjectInspector init(final Mode mode, final ObjectInspector[] parameters) throws HiveException {
     super.init(mode, parameters);
-    inputInspector_ = (PrimitiveObjectInspector) parameters[0];
+    this.inputInspector_ = (PrimitiveObjectInspector) parameters[0];
 
     // Parameters:
     // In PARTIAL1 and COMPLETE mode, the parameters are original data.
     // In PARTIAL2 and FINAL mode, the parameters are partial aggregations.
     if ((mode == Mode.PARTIAL1) || (mode == Mode.COMPLETE)) {
       if (parameters.length > 1) {
-        kInspector_ = (PrimitiveObjectInspector) parameters[1];
+        this.kInspector_ = (PrimitiveObjectInspector) parameters[1];
       }
     }
 
@@ -71,7 +71,7 @@
     if (data == null) { return; }
     final SketchState state = (SketchState) buf;
     final Memory serializedSketch = BytesWritableHelper.wrapAsMemory(
-        (BytesWritable) inputInspector_.getPrimitiveWritableObject(data));
+        (BytesWritable) this.inputInspector_.getPrimitiveWritableObject(data));
     state.update(KllFloatsSketch.heapify(serializedSketch));
   }
 
diff --git a/src/main/java/org/apache/datasketches/hive/kll/SketchState.java b/src/main/java/org/apache/datasketches/hive/kll/SketchState.java
index d8e2003..667183e 100644
--- a/src/main/java/org/apache/datasketches/hive/kll/SketchState.java
+++ b/src/main/java/org/apache/datasketches/hive/kll/SketchState.java
@@ -28,35 +28,35 @@
 
   // initialization is needed in the first phase (iterate) only
   void init() {
-    state_ = new KllFloatsSketch();
+    this.state_ = new KllFloatsSketch();
   }
 
   void init(final int k) {
-    state_ = new KllFloatsSketch(k);
+    this.state_ = new KllFloatsSketch(k);
   }
 
   boolean isInitialized() {
-    return state_ != null;
+    return this.state_ != null;
   }
 
   void update(final float value) {
-    state_.update(value);
+    this.state_.update(value);
   }
 
   void update(final KllFloatsSketch sketch) {
-    if (state_ == null) {
-      state_ = sketch;
+    if (this.state_ == null) {
+      this.state_ = sketch;
     } else {
-      state_.merge(sketch);
+      this.state_.merge(sketch);
     }
   }
 
   public KllFloatsSketch getResult() {
-    return state_;
+    return this.state_;
   }
 
   void reset() {
-    state_ = null;
+    this.state_ = null;
   }
 
 }
diff --git a/src/main/java/org/apache/datasketches/hive/kll/UnionSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/kll/UnionSketchUDAF.java
index 0fa69bd..86692f1 100644
--- a/src/main/java/org/apache/datasketches/hive/kll/UnionSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/kll/UnionSketchUDAF.java
@@ -57,8 +57,8 @@
       if (data[0] == null) { return; }
       final SketchState state = (SketchState) buf;
       if (!state.isInitialized()) {
-        if (kInspector_ != null) {
-          state.init(PrimitiveObjectInspectorUtils.getInt(data[1], kInspector_));
+        if (this.kInspector_ != null) {
+          state.init(PrimitiveObjectInspectorUtils.getInt(data[1], this.kInspector_));
         } else {
           state.init();
         }
diff --git a/src/main/java/org/apache/datasketches/hive/kll/Util.java b/src/main/java/org/apache/datasketches/hive/kll/Util.java
index 1886ef7..deb73f8 100644
--- a/src/main/java/org/apache/datasketches/hive/kll/Util.java
+++ b/src/main/java/org/apache/datasketches/hive/kll/Util.java
@@ -41,13 +41,13 @@
   }
 
   static List<Float> primitivesToList(final float[] array) {
-    final List<Float> result = new ArrayList<Float>(array.length);
+    final List<Float> result = new ArrayList<>(array.length);
     for (float item: array) { result.add(item); }
     return result;
   }
 
   static List<Double> primitivesToList(final double[] array) {
-    final List<Double> result = new ArrayList<Double>(array.length);
+    final List<Double> result = new ArrayList<>(array.length);
     for (double item: array) { result.add(item); }
     return result;
   }
diff --git a/src/main/java/org/apache/datasketches/hive/quantiles/DataToDoublesSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/quantiles/DataToDoublesSketchUDAF.java
index 8860da6..3d11269 100644
--- a/src/main/java/org/apache/datasketches/hive/quantiles/DataToDoublesSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/quantiles/DataToDoublesSketchUDAF.java
@@ -61,11 +61,11 @@
     public void iterate(final AggregationBuffer buf, final Object[] data) throws HiveException {
       if (data[0] == null) { return; }
       final DoublesUnionState state = (DoublesUnionState) buf;
-      if (!state.isInitialized() && (kObjectInspector != null)) {
-        final int k = PrimitiveObjectInspectorUtils.getInt(data[1], kObjectInspector);
+      if (!state.isInitialized() && (this.kObjectInspector != null)) {
+        final int k = PrimitiveObjectInspectorUtils.getInt(data[1], this.kObjectInspector);
         state.init(k);
       }
-      final double value = (double) inputObjectInspector.getPrimitiveJavaObject(data[0]);
+      final double value = (double) this.inputObjectInspector.getPrimitiveJavaObject(data[0]);
       state.update(value);
     }
 
diff --git a/src/main/java/org/apache/datasketches/hive/quantiles/DataToItemsSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/quantiles/DataToItemsSketchUDAF.java
index b7424a5..d69c58b 100644
--- a/src/main/java/org/apache/datasketches/hive/quantiles/DataToItemsSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/quantiles/DataToItemsSketchUDAF.java
@@ -66,11 +66,11 @@
       if (data[0] == null) { return; }
       @SuppressWarnings("unchecked")
       final ItemsUnionState<T> state = (ItemsUnionState<T>) buf;
-      if (!state.isInitialized() && (kObjectInspector != null)) {
-        final int k = PrimitiveObjectInspectorUtils.getInt(data[1], kObjectInspector);
+      if (!state.isInitialized() && (this.kObjectInspector != null)) {
+        final int k = PrimitiveObjectInspectorUtils.getInt(data[1], this.kObjectInspector);
         state.init(k);
       }
-      state.update(extractValue(data[0], inputObjectInspector));
+      state.update(extractValue(data[0], this.inputObjectInspector));
     }
 
     public abstract T extractValue(final Object data, final ObjectInspector objectInspector)
diff --git a/src/main/java/org/apache/datasketches/hive/quantiles/DataToStringsSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/quantiles/DataToStringsSketchUDAF.java
index 4b21eda..ca495dd 100644
--- a/src/main/java/org/apache/datasketches/hive/quantiles/DataToStringsSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/quantiles/DataToStringsSketchUDAF.java
@@ -52,7 +52,7 @@
     @Override
     public String extractValue(final Object data, final ObjectInspector objectInspector)
         throws HiveException {
-      final Object value = inputObjectInspector.getPrimitiveJavaObject(data);
+      final Object value = this.inputObjectInspector.getPrimitiveJavaObject(data);
       if (value instanceof String) {
         return (String) value;
       } else if (value instanceof HiveChar) {
diff --git a/src/main/java/org/apache/datasketches/hive/quantiles/DoublesEvaluator.java b/src/main/java/org/apache/datasketches/hive/quantiles/DoublesEvaluator.java
index 62b7947..e893498 100644
--- a/src/main/java/org/apache/datasketches/hive/quantiles/DoublesEvaluator.java
+++ b/src/main/java/org/apache/datasketches/hive/quantiles/DoublesEvaluator.java
@@ -38,14 +38,14 @@
   @Override
   public ObjectInspector init(final Mode mode, final ObjectInspector[] parameters) throws HiveException {
     super.init(mode, parameters);
-    inputObjectInspector = (PrimitiveObjectInspector) parameters[0];
+    this.inputObjectInspector = (PrimitiveObjectInspector) parameters[0];
 
     // Parameters:
     // In PARTIAL1 and COMPLETE mode, the parameters are original data.
     // In PARTIAL2 and FINAL mode, the parameters are partial aggregations.
     if (mode == Mode.PARTIAL1 || mode == Mode.COMPLETE) {
       if (parameters.length > 1) {
-        kObjectInspector = (PrimitiveObjectInspector) parameters[1];
+        this.kObjectInspector = (PrimitiveObjectInspector) parameters[1];
       }
     }
 
@@ -71,7 +71,7 @@
     if (data == null) { return; }
     final DoublesUnionState state = (DoublesUnionState) buf;
     final Memory serializedSketch = BytesWritableHelper.wrapAsMemory(
-        (BytesWritable) inputObjectInspector.getPrimitiveWritableObject(data));
+        (BytesWritable) this.inputObjectInspector.getPrimitiveWritableObject(data));
     state.update(serializedSketch);
   }
 
diff --git a/src/main/java/org/apache/datasketches/hive/quantiles/DoublesUnionState.java b/src/main/java/org/apache/datasketches/hive/quantiles/DoublesUnionState.java
index 653f2ce..cb6f03c 100644
--- a/src/main/java/org/apache/datasketches/hive/quantiles/DoublesUnionState.java
+++ b/src/main/java/org/apache/datasketches/hive/quantiles/DoublesUnionState.java
@@ -33,36 +33,36 @@
   void init(final int k) {
     final DoublesUnionBuilder unionBuilder = DoublesUnion.builder();
     if (k > 0) { unionBuilder.setMaxK(k); }
-    union = unionBuilder.build();
+    this.union = unionBuilder.build();
   }
 
   boolean isInitialized() {
-    return union != null;
+    return this.union != null;
   }
 
   void update(final double value) {
-    if (union == null) {
-      union = DoublesUnion.builder().build();
+    if (this.union == null) {
+      this.union = DoublesUnion.builder().build();
     }
-    union.update(value);
+    this.union.update(value);
   }
 
   void update(final Memory serializedSketch) {
     final DoublesSketch incomingSketch = DoublesSketch.wrap(serializedSketch);
-    if (union == null) {
-      union = DoublesUnion.heapify(incomingSketch);
+    if (this.union == null) {
+      this.union = DoublesUnion.heapify(incomingSketch);
     } else {
-      union.update(incomingSketch);
+      this.union.update(incomingSketch);
     }
   }
 
   public DoublesSketch getResult() {
-    if (union == null) { return null; }
-    return union.getResultAndReset();
+    if (this.union == null) { return null; }
+    return this.union.getResultAndReset();
   }
 
   void reset() {
-    union = null;
+    this.union = null;
   }
 
 }
diff --git a/src/main/java/org/apache/datasketches/hive/quantiles/ItemsEvaluator.java b/src/main/java/org/apache/datasketches/hive/quantiles/ItemsEvaluator.java
index b2343ef..4713974 100644
--- a/src/main/java/org/apache/datasketches/hive/quantiles/ItemsEvaluator.java
+++ b/src/main/java/org/apache/datasketches/hive/quantiles/ItemsEvaluator.java
@@ -41,21 +41,21 @@
   protected PrimitiveObjectInspector kObjectInspector;
 
   ItemsEvaluator(final Comparator<? super T> comparator, final ArrayOfItemsSerDe<T> serDe) {
-    comparator_ = comparator;
-    serDe_ = serDe;
+    this.comparator_ = comparator;
+    this.serDe_ = serDe;
   }
 
   @Override
   public ObjectInspector init(final Mode mode, final ObjectInspector[] parameters) throws HiveException {
     super.init(mode, parameters);
-    inputObjectInspector = (PrimitiveObjectInspector) parameters[0];
+    this.inputObjectInspector = (PrimitiveObjectInspector) parameters[0];
 
     // Parameters:
     // In PARTIAL1 and COMPLETE mode, the parameters are original data.
     // In PARTIAL2 and FINAL mode, the parameters are partial aggregations.
     if (mode == Mode.PARTIAL1 || mode == Mode.COMPLETE) {
       if (parameters.length > 1) {
-        kObjectInspector = (PrimitiveObjectInspector) parameters[1];
+        this.kObjectInspector = (PrimitiveObjectInspector) parameters[1];
       }
     }
 
@@ -83,7 +83,7 @@
     @SuppressWarnings("unchecked")
     final ItemsUnionState<T> state = (ItemsUnionState<T>) buf;
     final Memory serializedSketch = BytesWritableHelper.wrapAsMemory(
-        (BytesWritable) inputObjectInspector.getPrimitiveWritableObject(data));
+        (BytesWritable) this.inputObjectInspector.getPrimitiveWritableObject(data));
     state.update(serializedSketch);
   }
 
@@ -94,13 +94,13 @@
     final ItemsUnionState<T> state = (ItemsUnionState<T>) buf;
     final ItemsSketch<T> resultSketch = state.getResult();
     if (resultSketch == null) { return null; }
-    return new BytesWritable(resultSketch.toByteArray(serDe_));
+    return new BytesWritable(resultSketch.toByteArray(this.serDe_));
   }
 
   @SuppressWarnings("deprecation")
   @Override
   public AggregationBuffer getNewAggregationBuffer() throws HiveException {
-    return new ItemsUnionState<T>(comparator_, serDe_);
+    return new ItemsUnionState<>(this.comparator_, this.serDe_);
   }
 
 }
diff --git a/src/main/java/org/apache/datasketches/hive/quantiles/ItemsUnionState.java b/src/main/java/org/apache/datasketches/hive/quantiles/ItemsUnionState.java
index 9e7ee31..b7004d3 100644
--- a/src/main/java/org/apache/datasketches/hive/quantiles/ItemsUnionState.java
+++ b/src/main/java/org/apache/datasketches/hive/quantiles/ItemsUnionState.java
@@ -34,47 +34,47 @@
   private ItemsUnion<T> union;
 
   ItemsUnionState(final Comparator<? super T> comparator, final ArrayOfItemsSerDe<T> serDe) {
-    comparator_ = comparator;
-    serDe_ = serDe;
+    this.comparator_ = comparator;
+    this.serDe_ = serDe;
   }
 
   // initializing is needed only in the first phase (iterate)
   void init(final int k) {
     if (k > 0) {
-      union = ItemsUnion.getInstance(k, comparator_);
+      this.union = ItemsUnion.getInstance(k, this.comparator_);
     } else {
-      union = ItemsUnion.getInstance(comparator_);
+      this.union = ItemsUnion.getInstance(this.comparator_);
     }
   }
 
   boolean isInitialized() {
-    return union != null;
+    return this.union != null;
   }
 
   void update(final T value) {
-    if (union == null) {
-      union = ItemsUnion.getInstance(comparator_);
+    if (this.union == null) {
+      this.union = ItemsUnion.getInstance(this.comparator_);
     }
-    union.update(value);
+    this.union.update(value);
   }
 
   void update(final Memory serializedSketch) {
     final ItemsSketch<T> incomingSketch =
-        ItemsSketch.getInstance(serializedSketch, comparator_, serDe_);
-    if (union == null) {
-      union = ItemsUnion.getInstance(incomingSketch);
+        ItemsSketch.getInstance(serializedSketch, this.comparator_, this.serDe_);
+    if (this.union == null) {
+      this.union = ItemsUnion.getInstance(incomingSketch);
     } else {
-      union.update(incomingSketch);
+      this.union.update(incomingSketch);
     }
   }
 
   public ItemsSketch<T> getResult() {
-    if (union == null) { return null; }
-    return union.getResultAndReset();
+    if (this.union == null) { return null; }
+    return this.union.getResultAndReset();
   }
 
   void reset() {
-    union = null;
+    this.union = null;
   }
 
 }
diff --git a/src/main/java/org/apache/datasketches/hive/quantiles/UnionDoublesSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/quantiles/UnionDoublesSketchUDAF.java
index d746a54..911b6e8 100644
--- a/src/main/java/org/apache/datasketches/hive/quantiles/UnionDoublesSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/quantiles/UnionDoublesSketchUDAF.java
@@ -58,8 +58,8 @@
       final DoublesUnionState state = (DoublesUnionState) buf;
       if (!state.isInitialized()) {
         int k = 0;
-        if (kObjectInspector != null) {
-          k = PrimitiveObjectInspectorUtils.getInt(data[1], kObjectInspector);
+        if (this.kObjectInspector != null) {
+          k = PrimitiveObjectInspectorUtils.getInt(data[1], this.kObjectInspector);
         }
         state.init(k);
       }
diff --git a/src/main/java/org/apache/datasketches/hive/quantiles/UnionItemsSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/quantiles/UnionItemsSketchUDAF.java
index 3c93a5c..ae53ef7 100644
--- a/src/main/java/org/apache/datasketches/hive/quantiles/UnionItemsSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/quantiles/UnionItemsSketchUDAF.java
@@ -68,8 +68,8 @@
       final ItemsUnionState<T> state = (ItemsUnionState<T>) buf;
       if (!state.isInitialized()) {
         int k = 0;
-        if (kObjectInspector != null) {
-          k = PrimitiveObjectInspectorUtils.getInt(data[1], kObjectInspector);
+        if (this.kObjectInspector != null) {
+          k = PrimitiveObjectInspectorUtils.getInt(data[1], this.kObjectInspector);
         }
         state.init(k);
       }
diff --git a/src/main/java/org/apache/datasketches/hive/quantiles/Util.java b/src/main/java/org/apache/datasketches/hive/quantiles/Util.java
index 2aea43c..aea22b5 100644
--- a/src/main/java/org/apache/datasketches/hive/quantiles/Util.java
+++ b/src/main/java/org/apache/datasketches/hive/quantiles/Util.java
@@ -33,7 +33,7 @@
   }
 
   static List<Double> primitivesToList(final double[] array) {
-    final List<Double> result = new ArrayList<Double>(array.length);
+    final List<Double> result = new ArrayList<>(array.length);
     for (double item: array) { result.add(item); }
     return result;
   }
diff --git a/src/main/java/org/apache/datasketches/hive/theta/DataToSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/theta/DataToSketchUDAF.java
index 9bcad81..1b579d3 100644
--- a/src/main/java/org/apache/datasketches/hive/theta/DataToSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/theta/DataToSketchUDAF.java
@@ -149,19 +149,19 @@
 
       if (mode == Mode.PARTIAL1 || mode == Mode.COMPLETE) {
         // input is original data
-        inputObjectInspector = (PrimitiveObjectInspector) parameters[0];
+        this.inputObjectInspector = (PrimitiveObjectInspector) parameters[0];
         if (parameters.length > 1) {
-          nominalEntriesObjectInspector = (PrimitiveObjectInspector) parameters[1];
+          this.nominalEntriesObjectInspector = (PrimitiveObjectInspector) parameters[1];
         }
         if (parameters.length > 2) {
-          samplingProbabilityObjectInspector = (PrimitiveObjectInspector) parameters[2];
+          this.samplingProbabilityObjectInspector = (PrimitiveObjectInspector) parameters[2];
         }
         if (parameters.length > 3) {
-          seedObjectInspector = (PrimitiveObjectInspector) parameters[3];
+          this.seedObjectInspector = (PrimitiveObjectInspector) parameters[3];
         }
       } else {
         // input for PARTIAL2 and FINAL is the output from PARTIAL1
-        intermediateObjectInspector = (StructObjectInspector) parameters[0];
+        this.intermediateObjectInspector = (StructObjectInspector) parameters[0];
       }
 
       if (mode == Mode.PARTIAL1 || mode == Mode.PARTIAL2) {
@@ -196,22 +196,22 @@
       if (!state.isInitialized()) {
         initializeState(state, parameters);
       }
-      state.update(parameters[0], inputObjectInspector);
+      state.update(parameters[0], this.inputObjectInspector);
     }
 
     private void initializeState(final UnionState state, final Object[] parameters) {
       int sketchSize = DEFAULT_NOMINAL_ENTRIES;
-      if (nominalEntriesObjectInspector != null) {
-        sketchSize = PrimitiveObjectInspectorUtils.getInt(parameters[1], nominalEntriesObjectInspector);
+      if (this.nominalEntriesObjectInspector != null) {
+        sketchSize = PrimitiveObjectInspectorUtils.getInt(parameters[1], this.nominalEntriesObjectInspector);
       }
       float samplingProbability = UnionState.DEFAULT_SAMPLING_PROBABILITY;
-      if (samplingProbabilityObjectInspector != null) {
+      if (this.samplingProbabilityObjectInspector != null) {
         samplingProbability = PrimitiveObjectInspectorUtils.getFloat(parameters[2],
-            samplingProbabilityObjectInspector);
+            this.samplingProbabilityObjectInspector);
       }
       long seed = DEFAULT_UPDATE_SEED;
-      if (seedObjectInspector != null) {
-        seed = PrimitiveObjectInspectorUtils.getLong(parameters[3], seedObjectInspector);
+      if (this.seedObjectInspector != null) {
+        seed = PrimitiveObjectInspectorUtils.getLong(parameters[3], this.seedObjectInspector);
       }
       state.init(sketchSize, samplingProbability, seed);
     }
diff --git a/src/main/java/org/apache/datasketches/hive/theta/IntersectSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/theta/IntersectSketchUDAF.java
index 9403cde..26b2b01 100644
--- a/src/main/java/org/apache/datasketches/hive/theta/IntersectSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/theta/IntersectSketchUDAF.java
@@ -94,12 +94,12 @@
     public ObjectInspector init(final Mode mode, final ObjectInspector[] parameters) throws HiveException {
       super.init(mode, parameters);
       if (mode == Mode.PARTIAL1 || mode == Mode.COMPLETE) {
-        inputObjectInspector = (PrimitiveObjectInspector) parameters[0];
+        this.inputObjectInspector = (PrimitiveObjectInspector) parameters[0];
         if (parameters.length > 1) {
-          seedObjectInspector = (PrimitiveObjectInspector) parameters[1];
+          this.seedObjectInspector = (PrimitiveObjectInspector) parameters[1];
         }
       } else {
-        intermediateObjectInspector = (StandardStructObjectInspector) parameters[0];
+        this.intermediateObjectInspector = (StandardStructObjectInspector) parameters[0];
       }
 
       if (mode == Mode.PARTIAL1 || mode == Mode.PARTIAL2) {
@@ -125,12 +125,12 @@
       final IntersectionState state = (IntersectionState) buf;
       if (!state.isInitialized()) {
         long seed = DEFAULT_UPDATE_SEED;
-        if (seedObjectInspector != null) {
-          seed = PrimitiveObjectInspectorUtils.getLong(data[1], seedObjectInspector);
+        if (this.seedObjectInspector != null) {
+          seed = PrimitiveObjectInspectorUtils.getLong(data[1], this.seedObjectInspector);
         }
         state.init(seed);
       }
-      final byte[] serializedSketch = (byte[]) inputObjectInspector.getPrimitiveJavaObject(data[0]);
+      final byte[] serializedSketch = (byte[]) this.inputObjectInspector.getPrimitiveJavaObject(data[0]);
       if (serializedSketch == null) { return; }
       state.update(Memory.wrap(serializedSketch));
     }
@@ -154,14 +154,14 @@
       if (data == null) { return; }
       final IntersectionState state = (IntersectionState) buf;
       if (!state.isInitialized()) {
-        final long seed = ((LongWritable) intermediateObjectInspector.getStructFieldData(
-            data, intermediateObjectInspector.getStructFieldRef(SEED_FIELD))).get();
+        final long seed = ((LongWritable) this.intermediateObjectInspector.getStructFieldData(
+            data, this.intermediateObjectInspector.getStructFieldRef(SEED_FIELD))).get();
         state.init(seed);
       }
 
       final Memory serializedSketch = BytesWritableHelper.wrapAsMemory(
-          (BytesWritable) intermediateObjectInspector.getStructFieldData(
-          data, intermediateObjectInspector.getStructFieldRef(SKETCH_FIELD)));
+          (BytesWritable) this.intermediateObjectInspector.getStructFieldData(
+          data, this.intermediateObjectInspector.getStructFieldRef(SKETCH_FIELD)));
       state.update(serializedSketch);
     }
 
@@ -192,29 +192,29 @@
       private Intersection intersection_;
 
       boolean isInitialized() {
-        return intersection_ != null;
+        return this.intersection_ != null;
       }
 
       void init(final long seed) {
-        seed_ = seed;
-        intersection_ = SetOperation.builder().setSeed(seed).buildIntersection();
+        this.seed_ = seed;
+        this.intersection_ = SetOperation.builder().setSeed(seed).buildIntersection();
       }
 
       long getSeed() {
-        return seed_;
+        return this.seed_;
       }
 
       void update(final Memory serializedSketch) {
-        intersection_.intersect(Sketches.wrapSketch(serializedSketch, seed_));
+        this.intersection_.intersect(Sketches.wrapSketch(serializedSketch, this.seed_));
       }
 
       Sketch getResult() {
-        if (intersection_ == null) { return null; }
-        return intersection_.getResult();
+        if (this.intersection_ == null) { return null; }
+        return this.intersection_.getResult();
       }
 
       void reset() {
-        intersection_ = null;
+        this.intersection_ = null;
       }
     }
   }
diff --git a/src/main/java/org/apache/datasketches/hive/theta/UnionEvaluator.java b/src/main/java/org/apache/datasketches/hive/theta/UnionEvaluator.java
index ac86461..c09141e 100644
--- a/src/main/java/org/apache/datasketches/hive/theta/UnionEvaluator.java
+++ b/src/main/java/org/apache/datasketches/hive/theta/UnionEvaluator.java
@@ -90,16 +90,16 @@
       initializeState(state, partial);
     }
     final Memory serializedSketch = BytesWritableHelper.wrapAsMemory(
-        (BytesWritable) intermediateObjectInspector.getStructFieldData(
-            partial, intermediateObjectInspector.getStructFieldRef(SKETCH_FIELD)));
+        (BytesWritable) this.intermediateObjectInspector.getStructFieldData(
+            partial, this.intermediateObjectInspector.getStructFieldRef(SKETCH_FIELD)));
     state.update(serializedSketch);
   }
 
   private void initializeState(final UnionState state, final Object partial) {
-    final int nominalEntries = ((IntWritable) intermediateObjectInspector.getStructFieldData(
-        partial, intermediateObjectInspector.getStructFieldRef(NOMINAL_ENTRIES_FIELD))).get();
-    final long seed = ((LongWritable) intermediateObjectInspector.getStructFieldData(
-        partial, intermediateObjectInspector.getStructFieldRef(SEED_FIELD))).get();
+    final int nominalEntries = ((IntWritable) this.intermediateObjectInspector.getStructFieldData(
+        partial, this.intermediateObjectInspector.getStructFieldRef(NOMINAL_ENTRIES_FIELD))).get();
+    final long seed = ((LongWritable) this.intermediateObjectInspector.getStructFieldData(
+        partial, this.intermediateObjectInspector.getStructFieldRef(SEED_FIELD))).get();
     state.init(nominalEntries, seed);
   }
 
diff --git a/src/main/java/org/apache/datasketches/hive/theta/UnionSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/theta/UnionSketchUDAF.java
index 74b7ec0..893d857 100644
--- a/src/main/java/org/apache/datasketches/hive/theta/UnionSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/theta/UnionSketchUDAF.java
@@ -117,16 +117,16 @@
       super.init(mode, parameters);
 
       if (mode == Mode.PARTIAL1 || mode == Mode.COMPLETE) {
-        inputObjectInspector = (PrimitiveObjectInspector) parameters[0];
+        this.inputObjectInspector = (PrimitiveObjectInspector) parameters[0];
         if (parameters.length > 1) {
-          nominalEntriesObjectInspector = (PrimitiveObjectInspector) parameters[1];
+          this.nominalEntriesObjectInspector = (PrimitiveObjectInspector) parameters[1];
         }
         if (parameters.length > 2) {
-          seedObjectInspector = (PrimitiveObjectInspector) parameters[2];
+          this.seedObjectInspector = (PrimitiveObjectInspector) parameters[2];
         }
       } else {
         // mode = partial2 || final
-        intermediateObjectInspector = (StandardStructObjectInspector) parameters[0];
+        this.intermediateObjectInspector = (StandardStructObjectInspector) parameters[0];
       }
 
       if (mode == Mode.PARTIAL1 || mode == Mode.PARTIAL2) {
@@ -160,19 +160,19 @@
       if (!state.isInitialized()) {
         initializeState(state, parameters);
       }
-      final byte[] serializedSketch = (byte[]) inputObjectInspector.getPrimitiveJavaObject(parameters[0]);
+      final byte[] serializedSketch = (byte[]) this.inputObjectInspector.getPrimitiveJavaObject(parameters[0]);
       if (serializedSketch == null) { return; }
       state.update(Memory.wrap(serializedSketch));
     }
 
     private void initializeState(final UnionState state, final Object[] parameters) {
       int nominalEntries = DEFAULT_NOMINAL_ENTRIES;
-      if (nominalEntriesObjectInspector != null) {
-        nominalEntries = PrimitiveObjectInspectorUtils.getInt(parameters[1], nominalEntriesObjectInspector);
+      if (this.nominalEntriesObjectInspector != null) {
+        nominalEntries = PrimitiveObjectInspectorUtils.getInt(parameters[1], this.nominalEntriesObjectInspector);
       }
       long seed = DEFAULT_UPDATE_SEED;
-      if (seedObjectInspector != null) {
-        seed = PrimitiveObjectInspectorUtils.getLong(parameters[2], seedObjectInspector);
+      if (this.seedObjectInspector != null) {
+        seed = PrimitiveObjectInspectorUtils.getLong(parameters[2], this.seedObjectInspector);
       }
       state.init(nominalEntries, seed);
     }
diff --git a/src/main/java/org/apache/datasketches/hive/theta/UnionState.java b/src/main/java/org/apache/datasketches/hive/theta/UnionState.java
index 5a2a4c3..2ec365b 100644
--- a/src/main/java/org/apache/datasketches/hive/theta/UnionState.java
+++ b/src/main/java/org/apache/datasketches/hive/theta/UnionState.java
@@ -36,7 +36,7 @@
   private Union union_;
 
   public boolean isInitialized() {
-    return union_ != null;
+    return this.union_ != null;
   }
 
   // sampling probability is not relevant for merging
@@ -45,52 +45,52 @@
   }
 
   public void init(final int nominalEntries, final float samplingProbability, final long seed) {
-    nominalEntries_ = nominalEntries;
-    seed_ = seed;
-    union_ = SetOperation.builder().setNominalEntries(nominalEntries).setP(samplingProbability)
+    this.nominalEntries_ = nominalEntries;
+    this.seed_ = seed;
+    this.union_ = SetOperation.builder().setNominalEntries(nominalEntries).setP(samplingProbability)
         .setSeed(seed).buildUnion();
   }
 
   public int getNominalEntries() {
-    return nominalEntries_;
+    return this.nominalEntries_;
   }
 
   public long getSeed() {
-    return seed_;
+    return this.seed_;
   }
 
   public void update(final Memory mem) {
-    union_.union(mem);
+    this.union_.union(mem);
   }
 
   public void update(final Object value, final PrimitiveObjectInspector objectInspector) {
     switch (objectInspector.getPrimitiveCategory()) {
     case BINARY:
-      union_.update(PrimitiveObjectInspectorUtils.getBinary(value, objectInspector).copyBytes());
+      this.union_.update(PrimitiveObjectInspectorUtils.getBinary(value, objectInspector).copyBytes());
       return;
     case BYTE:
-      union_.update(PrimitiveObjectInspectorUtils.getByte(value, objectInspector));
+      this.union_.update(PrimitiveObjectInspectorUtils.getByte(value, objectInspector));
       return;
     case DOUBLE:
-      union_.update(PrimitiveObjectInspectorUtils.getDouble(value, objectInspector));
+      this.union_.update(PrimitiveObjectInspectorUtils.getDouble(value, objectInspector));
       return;
     case FLOAT:
-      union_.update(PrimitiveObjectInspectorUtils.getFloat(value, objectInspector));
+      this.union_.update(PrimitiveObjectInspectorUtils.getFloat(value, objectInspector));
       return;
     case INT:
-      union_.update(PrimitiveObjectInspectorUtils.getInt(value, objectInspector));
+      this.union_.update(PrimitiveObjectInspectorUtils.getInt(value, objectInspector));
       return;
     case LONG:
-      union_.update(PrimitiveObjectInspectorUtils.getLong(value, objectInspector));
+      this.union_.update(PrimitiveObjectInspectorUtils.getLong(value, objectInspector));
       return;
     case STRING:
-      union_.update(PrimitiveObjectInspectorUtils.getString(value, objectInspector));
+      this.union_.update(PrimitiveObjectInspectorUtils.getString(value, objectInspector));
       return;
     case CHAR:
-      union_.update(PrimitiveObjectInspectorUtils.getHiveChar(value, objectInspector).getValue());
+      this.union_.update(PrimitiveObjectInspectorUtils.getHiveChar(value, objectInspector).getValue());
       return;
     case VARCHAR:
-      union_.update(PrimitiveObjectInspectorUtils.getHiveVarchar(value, objectInspector).getValue());
+      this.union_.update(PrimitiveObjectInspectorUtils.getHiveVarchar(value, objectInspector).getValue());
       return;
     default:
       throw new IllegalArgumentException(
@@ -101,12 +101,12 @@
   }
 
   public Sketch getResult() {
-    if (union_ == null) { return null; }
-    return union_.getResult();
+    if (this.union_ == null) { return null; }
+    return this.union_.getResult();
   }
 
   public void reset() {
-    union_ = null;
+    this.union_ = null;
   }
 
 }
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchEvaluator.java b/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchEvaluator.java
index 4aca967..b27b4ec 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchEvaluator.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchEvaluator.java
@@ -64,16 +64,16 @@
       initializeState(state, data);
     }
     final Memory serializedSketch = BytesWritableHelper.wrapAsMemory(
-        (BytesWritable) intermediateInspector_.getStructFieldData(
-            data, intermediateInspector_.getStructFieldRef(SKETCH_FIELD)));
+        (BytesWritable) this.intermediateInspector_.getStructFieldData(
+            data, this.intermediateInspector_.getStructFieldRef(SKETCH_FIELD)));
     state.update(ArrayOfDoublesSketches.wrapSketch(serializedSketch));
   }
 
   private void initializeState(final ArrayOfDoublesUnionState state, final Object data) {
-    final int nominalNumEntries = ((IntWritable) intermediateInspector_.getStructFieldData(
-        data, intermediateInspector_.getStructFieldRef(NOMINAL_NUM_ENTRIES_FIELD))).get();
-    final int numValues = ((IntWritable) intermediateInspector_.getStructFieldData(
-        data, intermediateInspector_.getStructFieldRef(NUM_VALUES_FIELD))).get();
+    final int nominalNumEntries = ((IntWritable) this.intermediateInspector_.getStructFieldData(
+        data, this.intermediateInspector_.getStructFieldRef(NOMINAL_NUM_ENTRIES_FIELD))).get();
+    final int numValues = ((IntWritable) this.intermediateInspector_.getStructFieldData(
+        data, this.intermediateInspector_.getStructFieldRef(NUM_VALUES_FIELD))).get();
     state.init(nominalNumEntries, numValues);
   }
 
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchState.java b/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchState.java
index ea8adb9..0286ef8 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchState.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchState.java
@@ -30,12 +30,12 @@
   private ArrayOfDoublesUpdatableSketch sketch_;
 
   boolean isInitialized() {
-    return sketch_ != null;
+    return this.sketch_ != null;
   }
 
   void init(final int nominalNumEntries, final float samplingProbability, final int numValues) {
     super.init(nominalNumEntries, numValues);
-    sketch_ = new ArrayOfDoublesUpdatableSketchBuilder().setNominalEntries(nominalNumEntries)
+    this.sketch_ = new ArrayOfDoublesUpdatableSketchBuilder().setNominalEntries(nominalNumEntries)
         .setSamplingProbability(samplingProbability).setNumberOfValues(numValues).build();
   }
 
@@ -47,25 +47,25 @@
     }
     switch (keyInspector.getPrimitiveCategory()) {
     case BINARY:
-      sketch_.update(PrimitiveObjectInspectorUtils.getBinary(data[0], keyInspector).copyBytes(), values);
+      this.sketch_.update(PrimitiveObjectInspectorUtils.getBinary(data[0], keyInspector).copyBytes(), values);
       return;
     case BYTE:
-      sketch_.update(PrimitiveObjectInspectorUtils.getByte(data[0], keyInspector), values);
+      this.sketch_.update(PrimitiveObjectInspectorUtils.getByte(data[0], keyInspector), values);
       return;
     case DOUBLE:
-      sketch_.update(PrimitiveObjectInspectorUtils.getDouble(data[0], keyInspector), values);
+      this.sketch_.update(PrimitiveObjectInspectorUtils.getDouble(data[0], keyInspector), values);
       return;
     case FLOAT:
-      sketch_.update(PrimitiveObjectInspectorUtils.getFloat(data[0], keyInspector), values);
+      this.sketch_.update(PrimitiveObjectInspectorUtils.getFloat(data[0], keyInspector), values);
       return;
     case INT:
-      sketch_.update(PrimitiveObjectInspectorUtils.getInt(data[0], keyInspector), values);
+      this.sketch_.update(PrimitiveObjectInspectorUtils.getInt(data[0], keyInspector), values);
       return;
     case LONG:
-      sketch_.update(PrimitiveObjectInspectorUtils.getLong(data[0], keyInspector), values);
+      this.sketch_.update(PrimitiveObjectInspectorUtils.getLong(data[0], keyInspector), values);
       return;
     case STRING:
-      sketch_.update(PrimitiveObjectInspectorUtils.getString(data[0], keyInspector), values);
+      this.sketch_.update(PrimitiveObjectInspectorUtils.getString(data[0], keyInspector), values);
       return;
     default:
       throw new IllegalArgumentException(
@@ -76,16 +76,16 @@
 
   @Override
   ArrayOfDoublesSketch getResult() {
-    if (sketch_ == null) { return null; }
+    if (this.sketch_ == null) { return null; }
     // assumes that it is called once at the end of processing
     // since trimming to nominal number of entries is expensive
-    sketch_.trim();
-    return sketch_.compact();
+    this.sketch_.trim();
+    return this.sketch_.compact();
   }
 
   @Override
   void reset() {
-    sketch_ = null;
+    this.sketch_ = null;
   }
 
 }
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchToValuesUDTF.java b/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchToValuesUDTF.java
index 3532de0..0f2ee8d 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchToValuesUDTF.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchToValuesUDTF.java
@@ -53,10 +53,10 @@
       throw new UDFArgumentTypeException(0, "Primitive argument expected, but "
           + inspectors[0].getCategory().name() + " was recieved");
     }
-    inputObjectInspector = (PrimitiveObjectInspector) inspectors[0];
-    if (inputObjectInspector.getPrimitiveCategory() != PrimitiveObjectInspector.PrimitiveCategory.BINARY) {
+    this.inputObjectInspector = (PrimitiveObjectInspector) inspectors[0];
+    if (this.inputObjectInspector.getPrimitiveCategory() != PrimitiveObjectInspector.PrimitiveCategory.BINARY) {
       throw new UDFArgumentTypeException(0, "Binary value expected as the first argument, but "
-          + inputObjectInspector.getPrimitiveCategory().name() + " was recieved");
+          + this.inputObjectInspector.getPrimitiveCategory().name() + " was recieved");
     }
 
     return ObjectInspectorFactory.getStandardStructObjectInspector(
@@ -73,7 +73,7 @@
   public void process(final Object[] data) throws HiveException {
     if (data == null || data[0] == null) { return; }
     final BytesWritable serializedSketch =
-      (BytesWritable) inputObjectInspector.getPrimitiveWritableObject(data[0]);
+      (BytesWritable) this.inputObjectInspector.getPrimitiveWritableObject(data[0]);
     final ArrayOfDoublesSketch sketch = ArrayOfDoublesSketches.wrapSketch(
         BytesWritableHelper.wrapAsMemory(serializedSketch));
     final ArrayOfDoublesSketchIterator it = sketch.iterator();
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesState.java b/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesState.java
index ef93bb6..26a0675 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesState.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesState.java
@@ -28,16 +28,16 @@
   private int numValues_;
 
   void init(final int numNominalEntries, final int numValues) {
-    nominalNumEntries_ = numNominalEntries;
-    numValues_ = numValues;
+    this.nominalNumEntries_ = numNominalEntries;
+    this.numValues_ = numValues;
   }
 
   int getNominalNumEntries() {
-    return nominalNumEntries_;
+    return this.nominalNumEntries_;
   }
 
   int getNumValues() {
-    return numValues_;
+    return this.numValues_;
   }
 
   abstract ArrayOfDoublesSketch getResult();
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesUnionState.java b/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesUnionState.java
index 4d26653..69e1a28 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesUnionState.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesUnionState.java
@@ -28,29 +28,29 @@
   private ArrayOfDoublesUnion union_;
 
   boolean isInitialized() {
-    return union_ != null;
+    return this.union_ != null;
   }
 
   @Override
   void init(final int nominalNumEntries, final int numValues) {
     super.init(nominalNumEntries, numValues);
-    union_ = new ArrayOfDoublesSetOperationBuilder()
+    this.union_ = new ArrayOfDoublesSetOperationBuilder()
         .setNominalEntries(nominalNumEntries).setNumberOfValues(numValues).buildUnion();
   }
 
   void update(final ArrayOfDoublesSketch sketch) {
-    union_.union(sketch);
+    this.union_.union(sketch);
   }
 
   @Override
   ArrayOfDoublesSketch getResult() {
-    if (union_ == null) { return null; }
-    return union_.getResult();
+    if (this.union_ == null) { return null; }
+    return this.union_.getResult();
   }
 
   @Override
   void reset() {
-    union_ = null;
+    this.union_ = null;
   }
 
 }
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/DataToArrayOfDoublesSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/tuple/DataToArrayOfDoublesSketchUDAF.java
index dc6d3f2..b7edded 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/DataToArrayOfDoublesSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/DataToArrayOfDoublesSketchUDAF.java
@@ -106,31 +106,31 @@
     @Override
     public ObjectInspector init(final Mode mode, final ObjectInspector[] parameters) throws HiveException {
       super.init(mode, parameters);
-      mode_ = mode;
+      this.mode_ = mode;
       if ((mode == Mode.PARTIAL1) || (mode == Mode.COMPLETE)) {
         // input is original data
-        keyInspector_ = (PrimitiveObjectInspector) parameters[0];
-        numValues_ = 0;
-        while ((numValues_ + 1) < parameters.length) {
-          if (((PrimitiveObjectInspector) parameters[numValues_ + 1]).getPrimitiveCategory()
+        this.keyInspector_ = (PrimitiveObjectInspector) parameters[0];
+        this.numValues_ = 0;
+        while ((this.numValues_ + 1) < parameters.length) {
+          if (((PrimitiveObjectInspector) parameters[this.numValues_ + 1]).getPrimitiveCategory()
               != PrimitiveCategory.DOUBLE) {
             break;
           }
-          numValues_++;
+          this.numValues_++;
         }
-        valuesInspectors_ = new PrimitiveObjectInspector[numValues_];
-        for (int i = 0; i < numValues_; i++) {
-          valuesInspectors_[i] = (PrimitiveObjectInspector) parameters[i + 1];
+        this.valuesInspectors_ = new PrimitiveObjectInspector[this.numValues_];
+        for (int i = 0; i < this.numValues_; i++) {
+          this.valuesInspectors_[i] = (PrimitiveObjectInspector) parameters[i + 1];
         }
-        if (parameters.length > (numValues_ + 1)) {
-          nominalNumEntriesInspector_ = (PrimitiveObjectInspector) parameters[numValues_ + 1];
+        if (parameters.length > (this.numValues_ + 1)) {
+          this.nominalNumEntriesInspector_ = (PrimitiveObjectInspector) parameters[this.numValues_ + 1];
         }
-        if (parameters.length > (numValues_ + 2)) {
-          samplingProbabilityInspector_ = (PrimitiveObjectInspector) parameters[numValues_ + 2];
+        if (parameters.length > (this.numValues_ + 2)) {
+          this.samplingProbabilityInspector_ = (PrimitiveObjectInspector) parameters[this.numValues_ + 2];
         }
       } else {
         // input for PARTIAL2 and FINAL is the output from PARTIAL1
-        intermediateInspector_ = (StructObjectInspector) parameters[0];
+        this.intermediateInspector_ = (StructObjectInspector) parameters[0];
       }
 
       if ((mode == Mode.PARTIAL1) || (mode == Mode.PARTIAL2)) {
@@ -156,27 +156,27 @@
       if (!state.isInitialized()) {
         initializeState(state, data);
       }
-      state.update(data, keyInspector_, valuesInspectors_);
+      state.update(data, this.keyInspector_, this.valuesInspectors_);
     }
 
     private void initializeState(final ArrayOfDoublesSketchState state, final Object[] data) {
       int nominalNumEntries = DEFAULT_NOMINAL_ENTRIES;
-      if (nominalNumEntriesInspector_ != null) {
+      if (this.nominalNumEntriesInspector_ != null) {
         nominalNumEntries =
-            PrimitiveObjectInspectorUtils.getInt(data[numValues_ + 1], nominalNumEntriesInspector_);
+            PrimitiveObjectInspectorUtils.getInt(data[this.numValues_ + 1], this.nominalNumEntriesInspector_);
       }
       float samplingProbability = DEFAULT_SAMPLING_PROBABILITY;
-      if (samplingProbabilityInspector_ != null) {
-        samplingProbability = PrimitiveObjectInspectorUtils.getFloat(data[numValues_ + 2],
-            samplingProbabilityInspector_);
+      if (this.samplingProbabilityInspector_ != null) {
+        samplingProbability = PrimitiveObjectInspectorUtils.getFloat(data[this.numValues_ + 2],
+            this.samplingProbabilityInspector_);
       }
-      state.init(nominalNumEntries, samplingProbability, numValues_);
+      state.init(nominalNumEntries, samplingProbability, this.numValues_);
     }
 
     @SuppressWarnings("deprecation")
     @Override
     public AggregationBuffer getNewAggregationBuffer() throws HiveException {
-      if ((mode_ == Mode.PARTIAL1) || (mode_ == Mode.COMPLETE)) {
+      if ((this.mode_ == Mode.PARTIAL1) || (this.mode_ == Mode.COMPLETE)) {
         return new ArrayOfDoublesSketchState();
       }
       return new ArrayOfDoublesUnionState();
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/DataToDoubleSummaryWithModeSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/tuple/DataToDoubleSummaryWithModeSketchUDAF.java
index d668e81..16d6777 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/DataToDoubleSummaryWithModeSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/DataToDoubleSummaryWithModeSketchUDAF.java
@@ -100,7 +100,7 @@
     private DoubleSummary.Mode summaryMode_;
 
     public DataToDoubleSummaryWithModeSketchEvaluator() {
-      summaryMode_ = DoubleSummary.Mode.Sum;
+      this.summaryMode_ = DoubleSummary.Mode.Sum;
     }
 
     @Override
@@ -115,7 +115,7 @@
       if (mode == Mode.PARTIAL1 || mode == Mode.COMPLETE) {
         // input is original data
         if (inspectors.length > 4) {
-          summaryModeInspector_ = (PrimitiveObjectInspector) inspectors[4];
+          this.summaryModeInspector_ = (PrimitiveObjectInspector) inspectors[4];
         }
       }
       if (mode == Mode.PARTIAL1 || mode == Mode.PARTIAL2) {
@@ -134,12 +134,12 @@
 
     @Override
     protected SummaryFactory<DoubleSummary> getSummaryFactory(final Object[] data) {
-      if (summaryModeInspector_ != null) {
-        summaryMode_ = DoubleSummary.Mode.valueOf(
-          PrimitiveObjectInspectorUtils.getString(data[4], summaryModeInspector_)
+      if (this.summaryModeInspector_ != null) {
+        this.summaryMode_ = DoubleSummary.Mode.valueOf(
+          PrimitiveObjectInspectorUtils.getString(data[4], this.summaryModeInspector_)
         );
       }
-      return new DoubleSummaryFactory(summaryMode_);
+      return new DoubleSummaryFactory(this.summaryMode_);
     }
 
     @Override
@@ -158,16 +158,16 @@
       final byte[] bytes = intermediate.toByteArray();
       return Arrays.asList(
         new IntWritable(state.getNominalNumEntries()),
-        new Text(summaryMode_.toString()),
+        new Text(this.summaryMode_.toString()),
         new BytesWritable(bytes)
       );
     }
 
     @Override
     protected SummarySetOperations<DoubleSummary> getSummarySetOperationsForMerge(final Object data) {
-      summaryMode_ = DoubleSummary.Mode.valueOf(((Text) intermediateInspector_.getStructFieldData(
-          data, intermediateInspector_.getStructFieldRef(SUMMARY_MODE_FIELD))).toString());
-      return new DoubleSummarySetOperations(summaryMode_);
+      this.summaryMode_ = DoubleSummary.Mode.valueOf(((Text) this.intermediateInspector_.getStructFieldData(
+          data, this.intermediateInspector_.getStructFieldRef(SUMMARY_MODE_FIELD))).toString());
+      return new DoubleSummarySetOperations(this.summaryMode_);
     }
 
   }
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/DataToSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/tuple/DataToSketchUDAF.java
index 8b31f53..97ea58e 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/DataToSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/DataToSketchUDAF.java
@@ -112,20 +112,20 @@
     @Override
     public ObjectInspector init(final Mode mode, final ObjectInspector[] inspectors) throws HiveException {
       super.init(mode, inspectors);
-      mode_ = mode;
+      this.mode_ = mode;
       if (mode == Mode.PARTIAL1 || mode == Mode.COMPLETE) {
         // input is original data
-        keyInspector_ = (PrimitiveObjectInspector) inspectors[0];
-        valueInspector_ = (PrimitiveObjectInspector) inspectors[1];
+        this.keyInspector_ = (PrimitiveObjectInspector) inspectors[0];
+        this.valueInspector_ = (PrimitiveObjectInspector) inspectors[1];
         if (inspectors.length > 2) {
-          nominalNumEntriesInspector_ = (PrimitiveObjectInspector) inspectors[2];
+          this.nominalNumEntriesInspector_ = (PrimitiveObjectInspector) inspectors[2];
         }
         if (inspectors.length > 3) {
-          samplingProbabilityInspector_ = (PrimitiveObjectInspector) inspectors[3];
+          this.samplingProbabilityInspector_ = (PrimitiveObjectInspector) inspectors[3];
         }
       } else {
         // input for PARTIAL2 and FINAL is the output from PARTIAL1
-        intermediateInspector_ = (StructObjectInspector) inspectors[0];
+        this.intermediateInspector_ = (StructObjectInspector) inspectors[0];
       }
 
       if (mode == Mode.PARTIAL1 || mode == Mode.PARTIAL2) {
@@ -151,18 +151,18 @@
       if (!state.isInitialized()) {
         initializeState(state, data);
       }
-      state.update(data[0], keyInspector_, extractValue(data[1], valueInspector_));
+      state.update(data[0], this.keyInspector_, extractValue(data[1], this.valueInspector_));
     }
 
     private void initializeState(final SketchState<U, S> state, final Object[] data) {
       int nominalNumEntries = DEFAULT_NOMINAL_ENTRIES;
-      if (nominalNumEntriesInspector_ != null) {
-        nominalNumEntries = PrimitiveObjectInspectorUtils.getInt(data[2], nominalNumEntriesInspector_);
+      if (this.nominalNumEntriesInspector_ != null) {
+        nominalNumEntries = PrimitiveObjectInspectorUtils.getInt(data[2], this.nominalNumEntriesInspector_);
       }
       float samplingProbability = DEFAULT_SAMPLING_PROBABILITY;
-      if (samplingProbabilityInspector_ != null) {
+      if (this.samplingProbabilityInspector_ != null) {
         samplingProbability = PrimitiveObjectInspectorUtils.getFloat(data[3],
-            samplingProbabilityInspector_);
+            this.samplingProbabilityInspector_);
       }
       state.init(nominalNumEntries, samplingProbability, getSummaryFactory(data));
     }
@@ -170,7 +170,7 @@
     @SuppressWarnings("deprecation")
     @Override
     public AggregationBuffer getNewAggregationBuffer() throws HiveException {
-      if (mode_ == Mode.PARTIAL1 || mode_ == Mode.COMPLETE) {
+      if (this.mode_ == Mode.PARTIAL1 || this.mode_ == Mode.COMPLETE) {
         return new SketchState<U, S>();
       }
       return new UnionState<S>();
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/SketchEvaluator.java b/src/main/java/org/apache/datasketches/hive/tuple/SketchEvaluator.java
index 03449c2..3af36d5 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/SketchEvaluator.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/SketchEvaluator.java
@@ -91,16 +91,16 @@
       initializeState(state, data);
     }
     final BytesWritable serializedSketch =
-        (BytesWritable) intermediateInspector_.getStructFieldData(
-            data, intermediateInspector_.getStructFieldRef(SKETCH_FIELD));
+        (BytesWritable) this.intermediateInspector_.getStructFieldData(
+            data, this.intermediateInspector_.getStructFieldRef(SKETCH_FIELD));
     state.update(Sketches.heapifySketch(
         BytesWritableHelper.wrapAsMemory(serializedSketch),
         getSummaryDeserializer()));
   }
 
   protected void initializeState(final UnionState<S> state, final Object data) {
-    final int nominalNumEntries = ((IntWritable) intermediateInspector_.getStructFieldData(
-        data, intermediateInspector_.getStructFieldRef(NOMINAL_NUM_ENTRIES_FIELD))).get();
+    final int nominalNumEntries = ((IntWritable) this.intermediateInspector_.getStructFieldData(
+        data, this.intermediateInspector_.getStructFieldRef(NOMINAL_NUM_ENTRIES_FIELD))).get();
     state.init(nominalNumEntries, getSummarySetOperationsForMerge(data));
   }
 
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/SketchState.java b/src/main/java/org/apache/datasketches/hive/tuple/SketchState.java
index 14c17f8..ccc7093 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/SketchState.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/SketchState.java
@@ -32,38 +32,38 @@
   private UpdatableSketch<U, S> sketch_;
 
   boolean isInitialized() {
-    return sketch_ != null;
+    return this.sketch_ != null;
   }
 
   void init(final int nominalNumEntries, final float samplingProbability,
       final SummaryFactory<S> summaryFactory) {
     super.init(nominalNumEntries);
-    sketch_ = new UpdatableSketchBuilder<U, S>(summaryFactory).setNominalEntries(nominalNumEntries)
+    this.sketch_ = new UpdatableSketchBuilder<>(summaryFactory).setNominalEntries(nominalNumEntries)
         .setSamplingProbability(samplingProbability).build();
   }
 
   void update(final Object data, final PrimitiveObjectInspector keyObjectInspector, final U value) {
     switch (keyObjectInspector.getPrimitiveCategory()) {
     case BINARY:
-      sketch_.update(PrimitiveObjectInspectorUtils.getBinary(data, keyObjectInspector).copyBytes(), value);
+      this.sketch_.update(PrimitiveObjectInspectorUtils.getBinary(data, keyObjectInspector).copyBytes(), value);
       return;
     case BYTE:
-      sketch_.update(PrimitiveObjectInspectorUtils.getByte(data, keyObjectInspector), value);
+      this.sketch_.update(PrimitiveObjectInspectorUtils.getByte(data, keyObjectInspector), value);
       return;
     case DOUBLE:
-      sketch_.update(PrimitiveObjectInspectorUtils.getDouble(data, keyObjectInspector), value);
+      this.sketch_.update(PrimitiveObjectInspectorUtils.getDouble(data, keyObjectInspector), value);
       return;
     case FLOAT:
-      sketch_.update(PrimitiveObjectInspectorUtils.getFloat(data, keyObjectInspector), value);
+      this.sketch_.update(PrimitiveObjectInspectorUtils.getFloat(data, keyObjectInspector), value);
       return;
     case INT:
-      sketch_.update(PrimitiveObjectInspectorUtils.getInt(data, keyObjectInspector), value);
+      this.sketch_.update(PrimitiveObjectInspectorUtils.getInt(data, keyObjectInspector), value);
       return;
     case LONG:
-      sketch_.update(PrimitiveObjectInspectorUtils.getLong(data, keyObjectInspector), value);
+      this.sketch_.update(PrimitiveObjectInspectorUtils.getLong(data, keyObjectInspector), value);
       return;
     case STRING:
-      sketch_.update(PrimitiveObjectInspectorUtils.getString(data, keyObjectInspector), value);
+      this.sketch_.update(PrimitiveObjectInspectorUtils.getString(data, keyObjectInspector), value);
       return;
     default:
       throw new IllegalArgumentException(
@@ -74,16 +74,16 @@
 
   @Override
   Sketch<S> getResult() {
-    if (sketch_ == null) { return null; }
+    if (this.sketch_ == null) { return null; }
     // assumes that it is called once at the end of processing
     // since trimming to nominal number of entries is expensive
-    sketch_.trim();
-    return sketch_.compact();
+    this.sketch_.trim();
+    return this.sketch_.compact();
   }
 
   @Override
   void reset() {
-    sketch_ = null;
+    this.sketch_ = null;
   }
 
 }
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/State.java b/src/main/java/org/apache/datasketches/hive/tuple/State.java
index e2d774a..93b6c9e 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/State.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/State.java
@@ -28,11 +28,11 @@
   private int nominalNumEntries_;
 
   void init(final int nominalNumEntries) {
-    nominalNumEntries_ = nominalNumEntries;
+    this.nominalNumEntries_ = nominalNumEntries;
   }
 
   int getNominalNumEntries() {
-    return nominalNumEntries_;
+    return this.nominalNumEntries_;
   }
 
   abstract Sketch<S> getResult();
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/UnionArrayOfDoublesSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/tuple/UnionArrayOfDoublesSketchUDAF.java
index 3f62fb4..8f6a75d 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/UnionArrayOfDoublesSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/UnionArrayOfDoublesSketchUDAF.java
@@ -93,16 +93,16 @@
       super.init(mode, inspectors);
       if (mode == Mode.PARTIAL1 || mode == Mode.COMPLETE) {
         // input is original data
-        sketchInspector_ = (PrimitiveObjectInspector) inspectors[0];
+        this.sketchInspector_ = (PrimitiveObjectInspector) inspectors[0];
         if (inspectors.length > 1) {
-          nominalNumEntriesInspector_ = (PrimitiveObjectInspector) inspectors[1];
+          this.nominalNumEntriesInspector_ = (PrimitiveObjectInspector) inspectors[1];
         }
         if (inspectors.length > 2) {
-          numValuesInspector_ = (PrimitiveObjectInspector) inspectors[2];
+          this.numValuesInspector_ = (PrimitiveObjectInspector) inspectors[2];
         }
       } else {
         // input for PARTIAL2 and FINAL is the output from PARTIAL1
-        intermediateInspector_ = (StructObjectInspector) inspectors[0];
+        this.intermediateInspector_ = (StructObjectInspector) inspectors[0];
       }
 
       if (mode == Mode.PARTIAL1 || mode == Mode.PARTIAL2) {
@@ -128,19 +128,19 @@
       if (!state.isInitialized()) {
         initializeState(state, data);
       }
-      final byte[] serializedSketch = (byte[]) sketchInspector_.getPrimitiveJavaObject(data[0]);
+      final byte[] serializedSketch = (byte[]) this.sketchInspector_.getPrimitiveJavaObject(data[0]);
       if (serializedSketch == null) { return; }
       state.update(ArrayOfDoublesSketches.wrapSketch(Memory.wrap(serializedSketch)));
     }
 
     private void initializeState(final ArrayOfDoublesUnionState state, final Object[] data) {
       int nominalNumEntries = DEFAULT_NOMINAL_ENTRIES;
-      if (nominalNumEntriesInspector_ != null) {
-        nominalNumEntries = PrimitiveObjectInspectorUtils.getInt(data[1], nominalNumEntriesInspector_);
+      if (this.nominalNumEntriesInspector_ != null) {
+        nominalNumEntries = PrimitiveObjectInspectorUtils.getInt(data[1], this.nominalNumEntriesInspector_);
       }
       int numValues = DEFAULT_NUM_VALUES;
-      if (numValuesInspector_ != null) {
-        numValues = PrimitiveObjectInspectorUtils.getInt(data[2], numValuesInspector_);
+      if (this.numValuesInspector_ != null) {
+        numValues = PrimitiveObjectInspectorUtils.getInt(data[2], this.numValuesInspector_);
       }
       state.init(nominalNumEntries, numValues);
     }
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/UnionDoubleSummaryWithModeSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/tuple/UnionDoubleSummaryWithModeSketchUDAF.java
index feb8ff2..ffcbbe0 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/UnionDoubleSummaryWithModeSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/UnionDoubleSummaryWithModeSketchUDAF.java
@@ -88,7 +88,7 @@
     private DoubleSummary.Mode summaryMode_;
 
     public UnionDoubleSummaryWithModeSketchEvaluator() {
-      summaryMode_ = DoubleSummary.Mode.Sum;
+      this.summaryMode_ = DoubleSummary.Mode.Sum;
     }
 
     @Override
@@ -103,7 +103,7 @@
       if ((mode == Mode.PARTIAL1) || (mode == Mode.COMPLETE)) {
         // input is original data
         if (inspectors.length > 2) {
-          summaryModeInspector_ = (PrimitiveObjectInspector) inspectors[2];
+          this.summaryModeInspector_ = (PrimitiveObjectInspector) inspectors[2];
         }
       }
       if ((mode == Mode.PARTIAL1) || (mode == Mode.PARTIAL2)) {
@@ -127,12 +127,12 @@
 
     @Override
     protected SummarySetOperations<DoubleSummary> getSummarySetOperationsForIterate(final Object[] data) {
-      if (summaryModeInspector_ != null) {
-        summaryMode_ = DoubleSummary.Mode.valueOf(
-          PrimitiveObjectInspectorUtils.getString(data[2], summaryModeInspector_)
+      if (this.summaryModeInspector_ != null) {
+        this.summaryMode_ = DoubleSummary.Mode.valueOf(
+          PrimitiveObjectInspectorUtils.getString(data[2], this.summaryModeInspector_)
         );
       }
-      return new DoubleSummarySetOperations(summaryMode_);
+      return new DoubleSummarySetOperations(this.summaryMode_);
     }
 
     // need to add summary mode
@@ -146,16 +146,16 @@
       final byte[] bytes = intermediate.toByteArray();
       return Arrays.asList(
         new IntWritable(state.getNominalNumEntries()),
-        new Text(summaryMode_.toString()),
+        new Text(this.summaryMode_.toString()),
         new BytesWritable(bytes)
       );
     }
 
     @Override
     protected SummarySetOperations<DoubleSummary> getSummarySetOperationsForMerge(final Object data) {
-      summaryMode_ = DoubleSummary.Mode.valueOf(((Text) intermediateInspector_.getStructFieldData(
-          data, intermediateInspector_.getStructFieldRef(SUMMARY_MODE_FIELD))).toString());
-      return new DoubleSummarySetOperations(summaryMode_);
+      this.summaryMode_ = DoubleSummary.Mode.valueOf(((Text) this.intermediateInspector_.getStructFieldData(
+          data, this.intermediateInspector_.getStructFieldRef(SUMMARY_MODE_FIELD))).toString());
+      return new DoubleSummarySetOperations(this.summaryMode_);
     }
 
   }
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/UnionSketchUDAF.java b/src/main/java/org/apache/datasketches/hive/tuple/UnionSketchUDAF.java
index f097ff1..d1c5522 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/UnionSketchUDAF.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/UnionSketchUDAF.java
@@ -91,13 +91,13 @@
       super.init(mode, inspectors);
       if ((mode == Mode.PARTIAL1) || (mode == Mode.COMPLETE)) {
         // input is original data
-        sketchInspector_ = (PrimitiveObjectInspector) inspectors[0];
+        this.sketchInspector_ = (PrimitiveObjectInspector) inspectors[0];
         if (inspectors.length > 1) {
-          nominalNumEntriesInspector_ = (PrimitiveObjectInspector) inspectors[1];
+          this.nominalNumEntriesInspector_ = (PrimitiveObjectInspector) inspectors[1];
         }
       } else {
         // input for PARTIAL2 and FINAL is the output from PARTIAL1
-        intermediateInspector_ = (StructObjectInspector) inspectors[0];
+        this.intermediateInspector_ = (StructObjectInspector) inspectors[0];
       }
 
       if ((mode == Mode.PARTIAL1) || (mode == Mode.PARTIAL2)) {
@@ -123,15 +123,15 @@
       if (!state.isInitialized()) {
         initializeState(state, data);
       }
-      final byte[] serializedSketch = (byte[]) sketchInspector_.getPrimitiveJavaObject(data[0]);
+      final byte[] serializedSketch = (byte[]) this.sketchInspector_.getPrimitiveJavaObject(data[0]);
       if (serializedSketch == null) { return; }
       state.update(Sketches.heapifySketch(Memory.wrap(serializedSketch), getSummaryDeserializer()));
     }
 
     protected void initializeState(final UnionState<S> state, final Object[] data) {
       int nominalNumEntries = DEFAULT_NOMINAL_ENTRIES;
-      if (nominalNumEntriesInspector_ != null) {
-        nominalNumEntries = PrimitiveObjectInspectorUtils.getInt(data[1], nominalNumEntriesInspector_);
+      if (this.nominalNumEntriesInspector_ != null) {
+        nominalNumEntries = PrimitiveObjectInspectorUtils.getInt(data[1], this.nominalNumEntriesInspector_);
       }
       state.init(nominalNumEntries, getSummarySetOperationsForIterate(data));
     }
diff --git a/src/main/java/org/apache/datasketches/hive/tuple/UnionState.java b/src/main/java/org/apache/datasketches/hive/tuple/UnionState.java
index 4b19907..8a56f3a 100644
--- a/src/main/java/org/apache/datasketches/hive/tuple/UnionState.java
+++ b/src/main/java/org/apache/datasketches/hive/tuple/UnionState.java
@@ -29,27 +29,27 @@
   private Union<S> union_;
 
   boolean isInitialized() {
-    return union_ != null;
+    return this.union_ != null;
   }
 
   void init(final int nominalNumEntries, final SummarySetOperations<S> summarySetOps) {
     super.init(nominalNumEntries);
-    union_ = new Union<>(nominalNumEntries, summarySetOps);
+    this.union_ = new Union<>(nominalNumEntries, summarySetOps);
   }
 
   void update(final Sketch<S> sketch) {
-    union_.union(sketch);
+    this.union_.union(sketch);
   }
 
   @Override
   Sketch<S> getResult() {
-    if (union_ == null) { return null; }
-    return union_.getResult();
+    if (this.union_ == null) { return null; }
+    return this.union_.getResult();
   }
 
   @Override
   void reset() {
-    union_ = null;
+    this.union_ = null;
   }
 
 }
diff --git a/src/test/java/org/apache/datasketches/hive/frequencies/GetFrequentItemsFromStringsSketchUDTFTest.java b/src/test/java/org/apache/datasketches/hive/frequencies/GetFrequentItemsFromStringsSketchUDTFTest.java
index a8fd68e..12d4a07 100644
--- a/src/test/java/org/apache/datasketches/hive/frequencies/GetFrequentItemsFromStringsSketchUDTFTest.java
+++ b/src/test/java/org/apache/datasketches/hive/frequencies/GetFrequentItemsFromStringsSketchUDTFTest.java
@@ -106,6 +106,7 @@
     func.initialize(inspectors);
   }
 
+  @SuppressWarnings("synthetic-access")
   @Test
   public void normalCase() throws Exception {
     ObjectInspector[] inspectors = new ObjectInspector[] { binaryInspector, stringInspector };
@@ -173,7 +174,7 @@
 
     @Override
     public void collect(Object object) throws HiveException {
-      list.add(object);
+      this.list.add(object);
     }
 
   }
diff --git a/src/test/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchToValuesUDTFTest.java b/src/test/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchToValuesUDTFTest.java
index 66db4a7..4b0727e 100644
--- a/src/test/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchToValuesUDTFTest.java
+++ b/src/test/java/org/apache/datasketches/hive/tuple/ArrayOfDoublesSketchToValuesUDTFTest.java
@@ -88,7 +88,7 @@
      func.initialize(inspectors);
    }
 
-  @SuppressWarnings({ "deprecation", "unchecked" })
+  @SuppressWarnings({ "deprecation", "unchecked", "synthetic-access" })
   @Test
   public void normalCase() throws Exception {
     ObjectInspector[] inspectors = new ObjectInspector[] { binaryInspector };
@@ -124,7 +124,7 @@
 
     @Override
     public void collect(Object object) throws HiveException {
-      list.add(object);
+      this.list.add(object);
     }
 
   }