diff --git a/server/src/main/java/org/opensearch/index/codec/composite/DocValuesProvider.java b/server/src/main/java/org/opensearch/index/codec/composite/DocValuesProvider.java
deleted file mode 100644
index b92bce21b9f8e..0000000000000
--- a/server/src/main/java/org/opensearch/index/codec/composite/DocValuesProvider.java
+++ /dev/null
@@ -1,35 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- */
-
-package org.opensearch.index.codec.composite;
-
-import org.apache.lucene.codecs.DocValuesProducer;
-
-/**
- * An interface that provides access to document values for a specific field.
- *
- * @opensearch.experimental
- */
-public interface DocValuesProvider {
-
-    // /**
-    // * Returns the sorted numeric document values for the specified field.
-    // *
-    // * @param fieldName The name of the field for which to retrieve the sorted numeric document values.
-    // * @return The sorted numeric document values for the specified field.
-    // * @throws IOException If an error occurs while retrieving the sorted numeric document values.
-    // */
-    // SortedNumericDocValues getSortedNumeric(String fieldName) throws IOException;
-
-    /**
-     * Returns the DocValuesProducer instance.
-     *
-     * @return The DocValuesProducer instance.
-     */
-    DocValuesProducer getDocValuesProducer();
-}
diff --git a/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/aggregators/SumValueAggregator.java b/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/aggregators/SumValueAggregator.java
index cba002bcdb4c7..30309d629a765 100644
--- a/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/aggregators/SumValueAggregator.java
+++ b/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/aggregators/SumValueAggregator.java
@@ -16,9 +16,8 @@
  * <p>This implementation follows the Kahan summation algorithm to improve the accuracy
  * of the sum by tracking and compensating for the accumulated error in each iteration.
  *
- * @see <a href="http://en.wikipedia.org/wiki/Kahan_summation_algorithm">Kahan Summation Algorithm</a>
- *
  * @opensearch.experimental
+ * @see <a href="http://en.wikipedia.org/wiki/Kahan_summation_algorithm">Kahan Summation Algorithm</a>
  */
 class SumValueAggregator implements ValueAggregator<Double> {
 
@@ -67,11 +66,7 @@ public Double mergeAggregatedValues(Double value, Double aggregatedValue) {
         assert aggregatedValue == null || kahanSummation.value() == aggregatedValue;
         // add takes care of the sum and compensation internally
         if (value != null) {
-            if (value != null) {
-                kahanSummation.add(value);
-            } else {
-                kahanSummation.add(getIdentityMetricValue());
-            }
+            kahanSummation.add(value);
         } else {
             kahanSummation.add(getIdentityMetricValue());
         }
diff --git a/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/builder/BaseStarTreeBuilder.java b/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/builder/BaseStarTreeBuilder.java
index 1d41ceb189ed2..dcecab15ef945 100644
--- a/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/builder/BaseStarTreeBuilder.java
+++ b/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/builder/BaseStarTreeBuilder.java
@@ -279,10 +279,11 @@ void appendDocumentsToStarTree(Iterator<StarTreeDocument> starTreeDocumentIterat
     private void serializeStarTree(int numSegmentStarTreeDocument, int numStarTreeDocs) throws IOException {
         // serialize the star tree data
         long dataFilePointer = dataOut.getFilePointer();
-        long totalStarTreeDataLength = StarTreeWriter.writeStarTree(dataOut, rootNode, numStarTreeNodes, starTreeField.getName());
+        StarTreeWriter starTreeWriter = new StarTreeWriter();
+        long totalStarTreeDataLength = starTreeWriter.writeStarTree(dataOut, rootNode, numStarTreeNodes, starTreeField.getName());
 
         // serialize the star tree meta
-        StarTreeWriter.writeStarTreeMetadata(
+        starTreeWriter.writeStarTreeMetadata(
             metaOut,
             starTreeField,
             metricAggregatorInfos,
diff --git a/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/builder/OnHeapStarTreeBuilder.java b/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/builder/OnHeapStarTreeBuilder.java
index c18c55e0bb1a5..5200ebdfb1cbe 100644
--- a/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/builder/OnHeapStarTreeBuilder.java
+++ b/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/builder/OnHeapStarTreeBuilder.java
@@ -125,7 +125,7 @@ Iterator<StarTreeDocument> mergeStarTrees(List<StarTreeValues> starTreeValuesSub
      * Returns an array of all the starTreeDocuments from all the segments
      * We only take the non-star documents from all the segments.
      *
-     * @param starTreeValuesSubs StarTreeValues from multiple segmentsx
+     * @param starTreeValuesSubs StarTreeValues from multiple segments
      * @return array of star tree documents
      */
     StarTreeDocument[] getSegmentsStarTreeDocuments(List<StarTreeValues> starTreeValuesSubs) throws IOException {
diff --git a/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/fileformats/StarTreeWriter.java b/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/fileformats/StarTreeWriter.java
index 779977d9878c5..b244820219fe7 100644
--- a/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/fileformats/StarTreeWriter.java
+++ b/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/fileformats/StarTreeWriter.java
@@ -42,7 +42,7 @@ public StarTreeWriter() {}
      * @return total size of the three
      * @throws IOException when star-tree data serialization fails
      */
-    public static long writeStarTree(IndexOutput dataOut, InMemoryTreeNode rootNode, int numNodes, String name) throws IOException {
+    public long writeStarTree(IndexOutput dataOut, InMemoryTreeNode rootNode, int numNodes, String name) throws IOException {
         return StarTreeDataWriter.writeStarTree(dataOut, rootNode, numNodes, name);
     }
 
@@ -58,7 +58,7 @@ public static long writeStarTree(IndexOutput dataOut, InMemoryTreeNode rootNode,
      * @param dataFileLength          data file length
      * @throws IOException when star-tree data serialization fails
      */
-    public static void writeStarTreeMetadata(
+    public void writeStarTreeMetadata(
         IndexOutput metaOut,
         StarTreeField starTreeField,
         List<MetricAggregatorInfo> metricAggregatorInfos,