diff --git a/opensearch/src/main/java/org/opensearch/sql/opensearch/storage/script/filter/lucene/relevance/SimpleQueryStringQuery.java b/opensearch/src/main/java/org/opensearch/sql/opensearch/storage/script/filter/lucene/relevance/SimpleQueryStringQuery.java
index 109236db8e..2e75c8c178 100644
--- a/opensearch/src/main/java/org/opensearch/sql/opensearch/storage/script/filter/lucene/relevance/SimpleQueryStringQuery.java
+++ b/opensearch/src/main/java/org/opensearch/sql/opensearch/storage/script/filter/lucene/relevance/SimpleQueryStringQuery.java
@@ -8,7 +8,6 @@
 import com.google.common.collect.ImmutableMap;
 import java.util.Iterator;
 import java.util.Objects;
-import java.util.stream.Collectors;
 import org.opensearch.index.query.Operator;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilders;
@@ -60,7 +59,7 @@ public QueryBuilder build(FunctionExpression func) {
         .tupleValue()
         .entrySet()
         .stream()
-        .collect(Collectors.toMap(e -> e.getKey(), e -> e.getValue().floatValue()));
+        .collect(ImmutableMap.toImmutableMap(e -> e.getKey(), e -> e.getValue().floatValue()));
 
     SimpleQueryStringBuilder queryBuilder = createQueryBuilder(null,
             query.getValue().valueOf(null).stringValue())