diff --git a/server/src/main/java/org/opensearch/search/startree/StarTreeQueryContext.java b/server/src/main/java/org/opensearch/search/startree/StarTreeQueryContext.java
index ca0ab9ce52f6e..78e6f0a12559a 100644
--- a/server/src/main/java/org/opensearch/search/startree/StarTreeQueryContext.java
+++ b/server/src/main/java/org/opensearch/search/startree/StarTreeQueryContext.java
@@ -172,11 +172,13 @@ private static boolean validateDateHistogramSupport(
         CompositeDataCubeFieldType compositeIndexFieldInfo,
         AggregatorFactory aggregatorFactory
     ) {
-        if (!(aggregatorFactory instanceof DateHistogramAggregatorFactory dateHistogramAggregatorFactory)
+        if (!(aggregatorFactory instanceof DateHistogramAggregatorFactory)
             || aggregatorFactory.getSubFactories().getFactories().length < 1) {
             return false;
         }
 
+        DateHistogramAggregatorFactory dateHistogramAggregatorFactory = (DateHistogramAggregatorFactory) aggregatorFactory;
+
         // Find the DateDimension in the dimensions list
         DateDimension starTreeDateDimension = null;
         for (Dimension dimension : compositeIndexFieldInfo.getDimensions()) {
diff --git a/server/src/main/java/org/opensearch/search/startree/StarTreeQueryHelper.java b/server/src/main/java/org/opensearch/search/startree/StarTreeQueryHelper.java
index edbccb53853d5..0ace3431fb772 100644
--- a/server/src/main/java/org/opensearch/search/startree/StarTreeQueryHelper.java
+++ b/server/src/main/java/org/opensearch/search/startree/StarTreeQueryHelper.java
@@ -34,6 +34,7 @@
 import java.util.Map;
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
+import java.util.stream.Collectors;
 
 /**
  * Helper class for building star-tree query
@@ -146,7 +147,7 @@ public static Dimension getMatchingDimensionOrThrow(String dimensionName, List<D
     }
 
     public static Dimension getMatchingDimensionOrNull(String dimensionName, List<Dimension> orderedDimensions) {
-        List<Dimension> matchingDimensions = orderedDimensions.stream().filter(x -> x.getField().equals(dimensionName)).toList();
+        List<Dimension> matchingDimensions = orderedDimensions.stream().filter(x -> x.getField().equals(dimensionName)).collect(Collectors.toList());
         if (matchingDimensions.size() != 1) {
             return null;
         }
diff --git a/server/src/main/java/org/opensearch/search/startree/filter/provider/DimensionFilterMapper.java b/server/src/main/java/org/opensearch/search/startree/filter/provider/DimensionFilterMapper.java
index 8afdb00864b22..dff9a1fda2153 100644
--- a/server/src/main/java/org/opensearch/search/startree/filter/provider/DimensionFilterMapper.java
+++ b/server/src/main/java/org/opensearch/search/startree/filter/provider/DimensionFilterMapper.java
@@ -363,13 +363,20 @@ public Optional<Long> getMatchingOrdinal(
                     case GTE:
                         return seekStatus == TermsEnum.SeekStatus.END ? Optional.empty() : Optional.of(termsEnum.ord());
                     case GT:
-                        return switch (seekStatus) {
-                            case END -> Optional.empty();
-                            case FOUND -> ((termsEnum.ord() + 1) < sortedSetIterator.getValueCount())
-                                ? Optional.of(termsEnum.ord() + 1)
-                                : Optional.empty();
-                            case NOT_FOUND -> Optional.of(termsEnum.ord());
-                        };
+                        switch (seekStatus) {
+                            case END:
+                                return Optional.empty();
+                            case FOUND:
+                                if ((termsEnum.ord() + 1) < sortedSetIterator.getValueCount()) {
+                                    return Optional.of(termsEnum.ord() + 1);
+                                } else {
+                                    return Optional.empty();
+                                }
+                            case NOT_FOUND:
+                                return Optional.of(termsEnum.ord());
+                            default:
+                                throw new IllegalStateException("Unexpected value: " + seekStatus);
+                        }
                     case LTE:
                         if (seekStatus == TermsEnum.SeekStatus.NOT_FOUND) {
                             return ((termsEnum.ord() - 1) >= 0) ? Optional.of(termsEnum.ord() - 1) : Optional.empty();