Merge pull request #272 from apache/FixJavadocWarningsMain

Fix javadoc warnings main
diff --git a/src/main/java/com/yahoo/sketches/ByteArrayUtil.java b/src/main/java/com/yahoo/sketches/ByteArrayUtil.java
index 5c973b4..000a6c7 100644
--- a/src/main/java/com/yahoo/sketches/ByteArrayUtil.java
+++ b/src/main/java/com/yahoo/sketches/ByteArrayUtil.java
@@ -19,6 +19,10 @@
 
 package com.yahoo.sketches;
 
+/**
+ * Useful methods for byte arrays.
+ * @author Lee Rhodes
+ */
 public final class ByteArrayUtil {
 
   /**
diff --git a/src/main/java/com/yahoo/sketches/cpc/CpcSketch.java b/src/main/java/com/yahoo/sketches/cpc/CpcSketch.java
index f05b8c7..d884adb 100644
--- a/src/main/java/com/yahoo/sketches/cpc/CpcSketch.java
+++ b/src/main/java/com/yahoo/sketches/cpc/CpcSketch.java
@@ -64,6 +64,10 @@
 public final class CpcSketch {
   private static final String LS = System.getProperty("line.separator");
   private static final double[] kxpByteLookup = new double[256];
+
+  /**
+   * The default Log_base2 of K
+   */
   public static final int DEFAULT_LG_K = 11;
   final long seed;
   //common variables
diff --git a/src/main/java/com/yahoo/sketches/fdt/Group.java b/src/main/java/com/yahoo/sketches/fdt/Group.java
index 5561131..f94f825 100644
--- a/src/main/java/com/yahoo/sketches/fdt/Group.java
+++ b/src/main/java/com/yahoo/sketches/fdt/Group.java
@@ -38,12 +38,11 @@
   private final static String hfmt =
       "%12s"  + "%15s"    + "%15s"    + "%15s"    + "%12s"   + "%12s"   + " %s";
 
+  /**
+   * Construct an empty Group
+   */
   public Group() { }
 
-  public Group copy() {
-    return new Group();
-  }
-
   /**
    * Specifies the parameters to be listed as columns
    * @param priKey the primary key of the FDT sketch
@@ -117,7 +116,7 @@
   /**
    * Note: this class has a natural ordering that is inconsistent with equals.
    * Ignore FindBugs EQ_COMPARETO_USE_OBJECT_EQUALS warning.
-   * @param that the Group to compare to
+   * @param that The Group to compare to
    */
   @Override
   public int compareTo(final Group that) {
diff --git a/src/main/java/com/yahoo/sketches/fdt/PostProcessor.java b/src/main/java/com/yahoo/sketches/fdt/PostProcessor.java
index 1a3bf08..9d7c038 100644
--- a/src/main/java/com/yahoo/sketches/fdt/PostProcessor.java
+++ b/src/main/java/com/yahoo/sketches/fdt/PostProcessor.java
@@ -140,7 +140,7 @@
         final double lb = sketch.getLowerBound(numStdDev, count);
         final double thresh = (double) count / sketch.getRetainedEntries();
         final double rse = (sketch.getUpperBound(1, count) / est) - 1.0;
-        final Group gp = group.copy();
+        final Group gp = new Group();
         gp.init(priKey, count, est, ub, lb, thresh, rse);
         list.add(gp);
       }
diff --git a/src/main/java/com/yahoo/sketches/hash/XxHash.java b/src/main/java/com/yahoo/sketches/hash/XxHash.java
index 13ff437..eb36ef8 100644
--- a/src/main/java/com/yahoo/sketches/hash/XxHash.java
+++ b/src/main/java/com/yahoo/sketches/hash/XxHash.java
@@ -47,7 +47,14 @@
   private static final long P4 = -8796714831421723037L;
   private static final long P5 =  2870177450012600261L;
 
-
+  /**
+   * Compute the has of the given Memory object.
+   * @param mem The given Memory object
+   * @param offsetBytes Starting at this offset in bytes
+   * @param lengthBytes Continuing for this number of bytes
+   * @param seed use this seed for the hash function
+   * @return return the resulting 64-bit hash value.
+   */
   public static long hash(final Memory mem, final long offsetBytes, final long lengthBytes,
       final long seed) {
     return mem.xxHash64(offsetBytes, lengthBytes, seed);
diff --git a/src/main/java/com/yahoo/sketches/hll/HllSketch.java b/src/main/java/com/yahoo/sketches/hll/HllSketch.java
index c052c7d..c38f17d 100644
--- a/src/main/java/com/yahoo/sketches/hll/HllSketch.java
+++ b/src/main/java/com/yahoo/sketches/hll/HllSketch.java
@@ -63,7 +63,15 @@
  * @author Kevin Lang
  */
 public class HllSketch extends BaseHllSketch {
+
+  /**
+   * The default Log_base2 of K
+   */
   public static final int DEFAULT_LG_K = 12;
+
+  /**
+   * The default HLL-TYPE is HLL_4
+   */
   public static final TgtHllType DEFAULT_HLL_TYPE = TgtHllType.HLL_4;
 
   private static final String LS = System.getProperty("line.separator");
diff --git a/src/main/java/com/yahoo/sketches/hll/TgtHllType.java b/src/main/java/com/yahoo/sketches/hll/TgtHllType.java
index 515069c..50bbafc 100644
--- a/src/main/java/com/yahoo/sketches/hll/TgtHllType.java
+++ b/src/main/java/com/yahoo/sketches/hll/TgtHllType.java
@@ -51,6 +51,7 @@
 
  * @author Lee Rhodes
  */
+@SuppressWarnings("javadoc")
 public enum TgtHllType { HLL_4, HLL_6, HLL_8;
 
   static final TgtHllType values[] = values();
diff --git a/src/main/java/com/yahoo/sketches/kll/KllFloatsSketch.java b/src/main/java/com/yahoo/sketches/kll/KllFloatsSketch.java
index 9e6a820..6ca4b9b 100644
--- a/src/main/java/com/yahoo/sketches/kll/KllFloatsSketch.java
+++ b/src/main/java/com/yahoo/sketches/kll/KllFloatsSketch.java
@@ -150,6 +150,9 @@
  */
 public class KllFloatsSketch {
 
+  /**
+   * The default value of K.
+   */
   public static final int DEFAULT_K = 200;
   static final int DEFAULT_M = 8;
   static final int MIN_K = DEFAULT_M;
@@ -479,7 +482,7 @@
     final float[] quantiles = new float[fractions.length];
     for (int i = 0; i < fractions.length; i++) {
       final double fraction = fractions[i];
-      if (fraction < 0.0 || fraction > 1.0) {
+      if ((fraction < 0.0) || (fraction > 1.0)) {
         throw new SketchesArgumentException("Fraction cannot be less than zero or greater than 1.0");
       }
       if      (fraction == 0.0) { quantiles[i] = minValue_; }
@@ -848,6 +851,9 @@
     return new KllFloatsSketch(mem);
   }
 
+  /**
+   * @return the iterator for this class
+   */
   public KllFloatsSketchIterator iterator() {
     return new KllFloatsSketchIterator(items_, levels_, numLevels_);
   }
diff --git a/src/main/java/com/yahoo/sketches/quantiles/DoublesSketch.java b/src/main/java/com/yahoo/sketches/quantiles/DoublesSketch.java
index 5706e0a..6405ebb 100644
--- a/src/main/java/com/yahoo/sketches/quantiles/DoublesSketch.java
+++ b/src/main/java/com/yahoo/sketches/quantiles/DoublesSketch.java
@@ -720,6 +720,9 @@
     }
   }
 
+  /**
+   * @return the iterator for this class
+   */
   public DoublesSketchIterator iterator() {
     return new DoublesSketchIterator(this, getBitPattern());
   }
diff --git a/src/main/java/com/yahoo/sketches/quantiles/ItemsSketch.java b/src/main/java/com/yahoo/sketches/quantiles/ItemsSketch.java
index aeebea8..a3b56b9 100644
--- a/src/main/java/com/yahoo/sketches/quantiles/ItemsSketch.java
+++ b/src/main/java/com/yahoo/sketches/quantiles/ItemsSketch.java
@@ -567,11 +567,17 @@
    return getN() == 0;
   }
 
+  /**
+   * @return true if this sketch is off-heap
+   */
   @SuppressWarnings("static-method")
   public boolean isDirect() {
     return false;
   }
 
+  /**
+   * @return true if in estimation mode
+   */
   public boolean isEstimationMode() {
     return getN() >= (2L * k_);
   }
@@ -684,6 +690,9 @@
     dstMem.putByteArray(0, byteArr, 0, byteArr.length);
   }
 
+  /**
+   * @return the iterator for this class
+   */
   public ItemsSketchIterator<T> iterator() {
     return new ItemsSketchIterator<>(this, bitPattern_);
   }
diff --git a/src/main/java/com/yahoo/sketches/quantiles/UpdateDoublesSketch.java b/src/main/java/com/yahoo/sketches/quantiles/UpdateDoublesSketch.java
index 0278805..47b1de7 100644
--- a/src/main/java/com/yahoo/sketches/quantiles/UpdateDoublesSketch.java
+++ b/src/main/java/com/yahoo/sketches/quantiles/UpdateDoublesSketch.java
@@ -56,6 +56,9 @@
     return HeapUpdateDoublesSketch.heapifyInstance(srcMem);
   }
 
+  /**
+   * @return a CompactDoublesSketch of this class
+   */
   public CompactDoublesSketch compact() {
     return compact(null);
   }
diff --git a/src/main/java/com/yahoo/sketches/sampling/SampleSubsetSummary.java b/src/main/java/com/yahoo/sketches/sampling/SampleSubsetSummary.java
index a56db37..05f3806 100644
--- a/src/main/java/com/yahoo/sketches/sampling/SampleSubsetSummary.java
+++ b/src/main/java/com/yahoo/sketches/sampling/SampleSubsetSummary.java
@@ -40,18 +40,30 @@
     this.totalSketchWeight = totalSketchWeight;
   }
 
+  /**
+   * @return the Lower Bound
+   */
   public double getLowerBound() {
     return lowerBound;
   }
 
+  /**
+   * @return the total sketch weight
+   */
   public double getTotalSketchWeight() {
     return totalSketchWeight;
   }
 
+  /**
+   * @return the Upper Bound
+   */
   public double getUpperBound() {
     return upperBound;
   }
 
+  /**
+   * @return the unique count estimate
+   */
   public double getEstimate() {
     return estimate;
   }
diff --git a/src/main/java/com/yahoo/sketches/sampling/VarOptItemsSamples.java b/src/main/java/com/yahoo/sketches/sampling/VarOptItemsSamples.java
index 58cc4f1..44dbbda 100644
--- a/src/main/java/com/yahoo/sketches/sampling/VarOptItemsSamples.java
+++ b/src/main/java/com/yahoo/sketches/sampling/VarOptItemsSamples.java
@@ -95,7 +95,9 @@
     boolean getMark() { return sketch_.getMark(idx_); }
   }
 
-  // standard iterator
+  /**
+   * The standard iterator
+   */
   public class VarOptItemsIterator implements Iterator<WeightedSample> {
     int currIdx_;
     int finalIdx_; // inclusive final index
diff --git a/src/main/java/com/yahoo/sketches/tuple/ArrayOfDoublesSetOperationBuilder.java b/src/main/java/com/yahoo/sketches/tuple/ArrayOfDoublesSetOperationBuilder.java
index fc1a658..20d2e21 100644
--- a/src/main/java/com/yahoo/sketches/tuple/ArrayOfDoublesSetOperationBuilder.java
+++ b/src/main/java/com/yahoo/sketches/tuple/ArrayOfDoublesSetOperationBuilder.java
@@ -32,7 +32,14 @@
   private int numValues_;
   private long seed_;
 
+  /**
+   * Default Nominal Entries (a.k.a. K)
+   */
   public static final int DEFAULT_NOMINAL_ENTRIES = 4096;
+
+  /**
+   * Default number of values
+   */
   public static final int DEFAULT_NUMBER_OF_VALUES = 1;
 
   /**
@@ -46,7 +53,7 @@
 
   /**
    * This is to set the nominal number of entries.
-   * @param nomEntries Nominal number of entries. Forced to the nearest power of 2 greater than 
+   * @param nomEntries Nominal number of entries. Forced to the nearest power of 2 greater than
    * given value.
    * @return this builder
    */
@@ -95,7 +102,7 @@
   }
 
   /**
-   * Creates an instance of ArrayOfDoublesIntersection based on the current configuration of the 
+   * Creates an instance of ArrayOfDoublesIntersection based on the current configuration of the
    * builder.
    * The new instance is allocated on the heap if the memory is not provided.
    * The number of nominal entries is not relevant to this, so it is ignored.
@@ -106,7 +113,7 @@
   }
 
   /**
-   * Creates an instance of ArrayOfDoublesIntersection based on the current configuration of the 
+   * Creates an instance of ArrayOfDoublesIntersection based on the current configuration of the
    * builder.
    * The new instance is allocated on the heap if the memory is not provided.
    * The number of nominal entries is not relevant to this, so it is ignored.