fix null stats

parquet-column/src/main/java/parquet/column/impl/ColumnWriterImpl.java

diff --git a/parquet-column/src/main/java/parquet/column/impl/ColumnWriterImpl.java b/parquet-column/src/main/java/parquet/column/impl/ColumnWriterImpl.java
index 217d9af..c0a1bef 100644
--- a/parquet-column/src/main/java/parquet/column/impl/ColumnWriterImpl.java
+++ b/parquet-column/src/main/java/parquet/column/impl/ColumnWriterImpl.java
@@ -66,7 +66,7 @@
     this.pageSizeThreshold = pageSizeThreshold;
     // initial check of memory usage. So that we have enough data to make an initial prediction
     this.valueCountForNextSizeCheck = INITIAL_COUNT_FOR_SIZE_CHECK;
-    this.statistics = Statistics.getStatsBasedOnType(this.path.getType());
+    initStatistics();
 
     ParquetProperties parquetProps = new ParquetProperties(dictionaryPageSizeThreshold, writerVersion, enableDictionary);
     this.repetitionLevelColumn = ParquetProperties.getColumnDescriptorValuesWriter(path.getMaxRepetitionLevel(), initialSizePerCol);
@@ -74,6 +74,10 @@
     this.dataColumn = parquetProps.getValuesWriter(path, initialSizePerCol);
   }
 
+  private void initStatistics() {
+    this.statistics = Statistics.getStatsBasedOnType(this.path.getType());
+  }
+
   private void log(Object value, int r, int d) {
     LOG.debug(path + " " + value + " r:" + r + " d:" + d);
   }
@@ -151,6 +155,7 @@
     definitionLevelColumn.reset();
     dataColumn.reset();
     valueCount = 0;
+    initStatistics();
   }
 
   @Override