diff --git a/core/src/main/java/org/opensearch/sql/ast/expression/AggregateFunction.java b/core/src/main/java/org/opensearch/sql/ast/expression/AggregateFunction.java
index 5335e3dfa2..6e837e90cc 100644
--- a/core/src/main/java/org/opensearch/sql/ast/expression/AggregateFunction.java
+++ b/core/src/main/java/org/opensearch/sql/ast/expression/AggregateFunction.java
@@ -5,9 +5,6 @@
 
 package org.opensearch.sql.ast.expression;
 
-import static java.util.Collections.emptyList;
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
@@ -44,7 +41,7 @@ public class AggregateFunction extends UnresolvedExpression {
   public AggregateFunction(String funcName, UnresolvedExpression field) {
     this.funcName = funcName;
     this.field = field;
-    this.argList = emptyList();
+    this.argList = List.of();
   }
 
   /**
@@ -57,13 +54,13 @@ public AggregateFunction(String funcName, UnresolvedExpression field) {
   public AggregateFunction(String funcName, UnresolvedExpression field, Boolean distinct) {
     this.funcName = funcName;
     this.field = field;
-    this.argList = emptyList();
+    this.argList = List.of();
     this.distinct = distinct;
   }
 
   @Override
   public List<UnresolvedExpression> getChild() {
-    return singletonList(field);
+    return List.of(field);
   }
 
   @Override
diff --git a/core/src/main/java/org/opensearch/sql/ast/expression/Argument.java b/core/src/main/java/org/opensearch/sql/ast/expression/Argument.java
index f187dcd1d9..b4e860811f 100644
--- a/core/src/main/java/org/opensearch/sql/ast/expression/Argument.java
+++ b/core/src/main/java/org/opensearch/sql/ast/expression/Argument.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.ast.expression;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
@@ -26,7 +24,7 @@ public class Argument extends UnresolvedExpression {
   //    private final DataType valueType;
   @Override
   public List<UnresolvedExpression> getChild() {
-    return singletonList(value);
+    return List.of(value);
   }
 
   @Override
diff --git a/core/src/main/java/org/opensearch/sql/ast/expression/In.java b/core/src/main/java/org/opensearch/sql/ast/expression/In.java
index 78c958a93e..00f4150242 100644
--- a/core/src/main/java/org/opensearch/sql/ast/expression/In.java
+++ b/core/src/main/java/org/opensearch/sql/ast/expression/In.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.ast.expression;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
@@ -29,7 +27,7 @@ public class In extends UnresolvedExpression {
 
   @Override
   public List<UnresolvedExpression> getChild() {
-    return singletonList(field);
+    return List.of(field);
   }
 
   @Override
diff --git a/core/src/main/java/org/opensearch/sql/ast/expression/Interval.java b/core/src/main/java/org/opensearch/sql/ast/expression/Interval.java
index 82ff1b93cf..6ffc86497d 100644
--- a/core/src/main/java/org/opensearch/sql/ast/expression/Interval.java
+++ b/core/src/main/java/org/opensearch/sql/ast/expression/Interval.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.ast.expression;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
@@ -30,7 +28,7 @@ public Interval(UnresolvedExpression value, String unit) {
 
   @Override
   public List<UnresolvedExpression> getChild() {
-    return singletonList(value);
+    return List.of(value);
   }
 
   @Override
diff --git a/core/src/main/java/org/opensearch/sql/ast/expression/Not.java b/core/src/main/java/org/opensearch/sql/ast/expression/Not.java
index 1dcb59c4b8..1794c75080 100644
--- a/core/src/main/java/org/opensearch/sql/ast/expression/Not.java
+++ b/core/src/main/java/org/opensearch/sql/ast/expression/Not.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.ast.expression;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
@@ -24,7 +22,7 @@ public class Not extends UnresolvedExpression {
 
   @Override
   public List<UnresolvedExpression> getChild() {
-    return singletonList(expression);
+    return List.of(expression);
   }
 
   @Override
diff --git a/core/src/main/java/org/opensearch/sql/ast/expression/UnresolvedArgument.java b/core/src/main/java/org/opensearch/sql/ast/expression/UnresolvedArgument.java
index 18fd13a4e7..cd826e8d90 100644
--- a/core/src/main/java/org/opensearch/sql/ast/expression/UnresolvedArgument.java
+++ b/core/src/main/java/org/opensearch/sql/ast/expression/UnresolvedArgument.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.ast.expression;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
@@ -28,7 +26,7 @@ public UnresolvedArgument(String argName, UnresolvedExpression value) {
 
   @Override
   public List<UnresolvedExpression> getChild() {
-    return singletonList(value);
+    return List.of(value);
   }
 
   @Override
diff --git a/core/src/main/java/org/opensearch/sql/ast/tree/RareTopN.java b/core/src/main/java/org/opensearch/sql/ast/tree/RareTopN.java
index 05f3a178a9..6c0d203a00 100644
--- a/core/src/main/java/org/opensearch/sql/ast/tree/RareTopN.java
+++ b/core/src/main/java/org/opensearch/sql/ast/tree/RareTopN.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.ast.tree;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.AllArgsConstructor;
 import lombok.EqualsAndHashCode;
@@ -42,7 +40,7 @@ public RareTopN attach(UnresolvedPlan child) {
 
   @Override
   public List<UnresolvedPlan> getChild() {
-    return singletonList(this.child);
+    return List.of(this.child);
   }
 
   @Override
diff --git a/core/src/main/java/org/opensearch/sql/expression/text/TextFunctions.java b/core/src/main/java/org/opensearch/sql/expression/text/TextFunctions.java
index 1c99af789a..b555c8c05c 100644
--- a/core/src/main/java/org/opensearch/sql/expression/text/TextFunctions.java
+++ b/core/src/main/java/org/opensearch/sql/expression/text/TextFunctions.java
@@ -5,7 +5,6 @@
 
 package org.opensearch.sql.expression.text;
 
-import static java.util.Collections.singletonList;
 import static org.opensearch.sql.data.type.ExprCoreType.ARRAY;
 import static org.opensearch.sql.data.type.ExprCoreType.INTEGER;
 import static org.opensearch.sql.data.type.ExprCoreType.STRING;
@@ -176,7 +175,7 @@ private DefaultFunctionResolver concat() {
         concatFuncName,
         funcName ->
             Pair.of(
-                new FunctionSignature(concatFuncName, singletonList(ARRAY)),
+                new FunctionSignature(concatFuncName, List.of(ARRAY)),
                 (funcProp, args) ->
                     new FunctionExpression(funcName, args) {
                       @Override
diff --git a/core/src/main/java/org/opensearch/sql/expression/window/ranking/RankingWindowFunction.java b/core/src/main/java/org/opensearch/sql/expression/window/ranking/RankingWindowFunction.java
index c119629cda..87f4b7de15 100644
--- a/core/src/main/java/org/opensearch/sql/expression/window/ranking/RankingWindowFunction.java
+++ b/core/src/main/java/org/opensearch/sql/expression/window/ranking/RankingWindowFunction.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.expression.window.ranking;
 
-import static java.util.Collections.emptyList;
-
 import java.util.List;
 import java.util.stream.Collectors;
 import org.apache.commons.lang3.tuple.Pair;
@@ -35,7 +33,7 @@ public abstract class RankingWindowFunction extends FunctionExpression
   protected int rank;
 
   public RankingWindowFunction(FunctionName functionName) {
-    super(functionName, emptyList());
+    super(functionName, List.of());
   }
 
   @Override
diff --git a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalAggregation.java b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalAggregation.java
index 450a4fe415..d40feb7dff 100644
--- a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalAggregation.java
+++ b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalAggregation.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.planner.logical;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
@@ -26,7 +24,7 @@ public class LogicalAggregation extends LogicalPlan {
   /** Constructor of LogicalAggregation. */
   public LogicalAggregation(
       LogicalPlan child, List<NamedAggregator> aggregatorList, List<NamedExpression> groupByList) {
-    super(singletonList(child));
+    super(List.of(child));
     this.aggregatorList = aggregatorList;
     this.groupByList = groupByList;
   }
diff --git a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalDedupe.java b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalDedupe.java
index 368dc3314f..33fbdfd00e 100644
--- a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalDedupe.java
+++ b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalDedupe.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.planner.logical;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
@@ -31,7 +29,7 @@ public LogicalDedupe(
       Integer allowedDuplication,
       Boolean keepEmpty,
       Boolean consecutive) {
-    super(singletonList(child));
+    super(List.of(child));
     this.dedupeList = dedupeList;
     this.allowedDuplication = allowedDuplication;
     this.keepEmpty = keepEmpty;
diff --git a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalEval.java b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalEval.java
index 2a79a0ad44..b93b80202e 100644
--- a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalEval.java
+++ b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalEval.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.planner.logical;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
@@ -28,7 +26,7 @@ public class LogicalEval extends LogicalPlan {
 
   /** Constructor of LogicalEval. */
   public LogicalEval(LogicalPlan child, List<Pair<ReferenceExpression, Expression>> expressions) {
-    super(singletonList(child));
+    super(List.of(child));
     this.expressions = expressions;
   }
 
diff --git a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalNested.java b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalNested.java
index 24d768865b..91eae51599 100644
--- a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalNested.java
+++ b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalNested.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.planner.logical;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import java.util.Map;
 import lombok.EqualsAndHashCode;
@@ -28,7 +26,7 @@ public LogicalNested(
       LogicalPlan childPlan,
       List<Map<String, ReferenceExpression>> fields,
       List<NamedExpression> projectList) {
-    super(singletonList(childPlan));
+    super(List.of(childPlan));
     this.fields = fields;
     this.projectList = projectList;
   }
diff --git a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalProject.java b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalProject.java
index 58576d2e59..37320f8428 100644
--- a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalProject.java
+++ b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalProject.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.planner.logical;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
@@ -26,7 +24,7 @@ public LogicalProject(
       LogicalPlan child,
       List<NamedExpression> projectList,
       List<NamedExpression> namedParseExpressions) {
-    super(singletonList(child));
+    super(List.of(child));
     this.projectList = projectList;
     this.namedParseExpressions = namedParseExpressions;
   }
diff --git a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalRareTopN.java b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalRareTopN.java
index 787350b5cb..17bb090f60 100644
--- a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalRareTopN.java
+++ b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalRareTopN.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.planner.logical;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
@@ -32,7 +30,7 @@ public LogicalRareTopN(
       Integer noOfResults,
       List<Expression> fieldList,
       List<Expression> groupByList) {
-    super(singletonList(child));
+    super(List.of(child));
     this.commandType = commandType;
     this.noOfResults = noOfResults;
     this.fieldList = fieldList;
diff --git a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalSort.java b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalSort.java
index 17f6ff0a97..f5b9164e59 100644
--- a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalSort.java
+++ b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalSort.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.planner.logical;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
@@ -25,7 +23,7 @@ public class LogicalSort extends LogicalPlan {
 
   /** Constructor of LogicalSort. */
   public LogicalSort(LogicalPlan child, List<Pair<SortOption, Expression>> sortList) {
-    super(singletonList(child));
+    super(List.of(child));
     this.sortList = sortList;
   }
 
diff --git a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalWrite.java b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalWrite.java
index 1f4d0ff108..76d75972d8 100644
--- a/core/src/main/java/org/opensearch/sql/planner/logical/LogicalWrite.java
+++ b/core/src/main/java/org/opensearch/sql/planner/logical/LogicalWrite.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.planner.logical;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
@@ -27,7 +25,7 @@ public class LogicalWrite extends LogicalPlan {
 
   /** Construct a logical write with given child node, table and column name list. */
   public LogicalWrite(LogicalPlan child, Table table, List<String> columns) {
-    super(singletonList(child));
+    super(List.of(child));
     this.table = table;
     this.columns = columns;
   }
diff --git a/core/src/main/java/org/opensearch/sql/planner/physical/FilterOperator.java b/core/src/main/java/org/opensearch/sql/planner/physical/FilterOperator.java
index 291b267484..02cfd127e7 100644
--- a/core/src/main/java/org/opensearch/sql/planner/physical/FilterOperator.java
+++ b/core/src/main/java/org/opensearch/sql/planner/physical/FilterOperator.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.planner.physical;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
@@ -37,7 +35,7 @@ public <R, C> R accept(PhysicalPlanNodeVisitor<R, C> visitor, C context) {
 
   @Override
   public List<PhysicalPlan> getChild() {
-    return singletonList(input);
+    return List.of(input);
   }
 
   @Override
diff --git a/core/src/main/java/org/opensearch/sql/storage/write/TableWriteOperator.java b/core/src/main/java/org/opensearch/sql/storage/write/TableWriteOperator.java
index 82607eaa65..b11eb35f0e 100644
--- a/core/src/main/java/org/opensearch/sql/storage/write/TableWriteOperator.java
+++ b/core/src/main/java/org/opensearch/sql/storage/write/TableWriteOperator.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.storage.write;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.RequiredArgsConstructor;
 import org.opensearch.sql.planner.physical.PhysicalPlan;
@@ -30,7 +28,7 @@ public <R, C> R accept(PhysicalPlanNodeVisitor<R, C> visitor, C context) {
 
   @Override
   public List<PhysicalPlan> getChild() {
-    return singletonList(input);
+    return List.of(input);
   }
 
   /**
diff --git a/core/src/test/java/org/opensearch/sql/analysis/SelectExpressionAnalyzerTest.java b/core/src/test/java/org/opensearch/sql/analysis/SelectExpressionAnalyzerTest.java
index 8898b0b7db..590f18f96f 100644
--- a/core/src/test/java/org/opensearch/sql/analysis/SelectExpressionAnalyzerTest.java
+++ b/core/src/test/java/org/opensearch/sql/analysis/SelectExpressionAnalyzerTest.java
@@ -5,7 +5,6 @@
 
 package org.opensearch.sql.analysis;
 
-import static java.util.Collections.singletonList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.doAnswer;
@@ -77,11 +76,11 @@ protected List<NamedExpression> analyze(UnresolvedExpression unresolvedExpressio
         .when(optimizer)
         .optimize(any(), any());
     return new SelectExpressionAnalyzer(expressionAnalyzer)
-        .analyze(singletonList(unresolvedExpression), analysisContext, optimizer);
+        .analyze(List.of(unresolvedExpression), analysisContext, optimizer);
   }
 
   protected void assertAnalyzeEqual(
       NamedExpression expected, UnresolvedExpression unresolvedExpression) {
-    assertEquals(singletonList(expected), analyze(unresolvedExpression));
+    assertEquals(List.of(expected), analyze(unresolvedExpression));
   }
 }
diff --git a/core/src/test/java/org/opensearch/sql/executor/ExplainTest.java b/core/src/test/java/org/opensearch/sql/executor/ExplainTest.java
index eaeae07242..bf6b1cca68 100644
--- a/core/src/test/java/org/opensearch/sql/executor/ExplainTest.java
+++ b/core/src/test/java/org/opensearch/sql/executor/ExplainTest.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.executor;
 
-import static java.util.Collections.emptyList;
-import static java.util.Collections.singletonList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.opensearch.sql.ast.tree.RareTopN.CommandType.TOP;
 import static org.opensearch.sql.ast.tree.Sort.SortOption.DEFAULT_ASC;
@@ -78,11 +76,11 @@ void can_explain_project_filter_table_scan() {
             new ExplainResponseNode(
                 "ProjectOperator",
                 Map.of("fields", "[name, age]"),
-                singletonList(
+                List.of(
                     new ExplainResponseNode(
                         "FilterOperator",
                         Map.of("conditions", "and(=(balance, 10000), >(age, 30))"),
-                        singletonList(tableScan.explainNode()))))),
+                        List.of(tableScan.explainNode()))))),
         explain.apply(plan));
   }
 
@@ -101,7 +99,7 @@ void can_explain_aggregations() {
                 Map.of(
                     "aggregators", "[avg(balance)]",
                     "groupBy", "[state]"),
-                singletonList(tableScan.explainNode()))),
+                List.of(tableScan.explainNode()))),
         explain.apply(plan));
   }
 
@@ -109,13 +107,13 @@ void can_explain_aggregations() {
   void can_explain_rare_top_n() {
     Expression field = ref("state", STRING);
 
-    PhysicalPlan plan = rareTopN(tableScan, TOP, emptyList(), field);
+    PhysicalPlan plan = rareTopN(tableScan, TOP, List.of(), field);
     assertEquals(
         new ExplainResponse(
             new ExplainResponseNode(
                 "RareTopNOperator",
                 Map.of("commandType", TOP, "noOfResults", 10, "fields", "[state]", "groupBy", "[]"),
-                singletonList(tableScan.explainNode()))),
+                List.of(tableScan.explainNode()))),
         explain.apply(plan));
   }
 
@@ -145,7 +143,7 @@ void can_explain_window() {
                             Map.of(
                                 "sortOrder", "ASC",
                                 "nullOrder", "NULL_FIRST")))),
-                singletonList(tableScan.explainNode()))),
+                List.of(tableScan.explainNode()))),
         explain.apply(plan));
   }
 
@@ -171,15 +169,15 @@ void can_explain_other_operators() {
             new ExplainResponseNode(
                 "RemoveOperator",
                 Map.of("removeList", "[state]"),
-                singletonList(
+                List.of(
                     new ExplainResponseNode(
                         "RenameOperator",
                         Map.of("mapping", Map.of("state", "s")),
-                        singletonList(
+                        List.of(
                             new ExplainResponseNode(
                                 "EvalOperator",
                                 Map.of("expressions", Map.of("age", "+(age, 2)")),
-                                singletonList(
+                                List.of(
                                     new ExplainResponseNode(
                                         "DedupeOperator",
                                         Map.of(
@@ -191,7 +189,7 @@ void can_explain_other_operators() {
                                             false,
                                             "consecutive",
                                             false),
-                                        singletonList(
+                                        List.of(
                                             new ExplainResponseNode(
                                                 "SortOperator",
                                                 Map.of(
@@ -201,11 +199,11 @@ void can_explain_other_operators() {
                                                         Map.of(
                                                             "sortOrder", "ASC",
                                                             "nullOrder", "NULL_FIRST"))),
-                                                singletonList(
+                                                List.of(
                                                     new ExplainResponseNode(
                                                         "ValuesOperator",
                                                         Map.of("values", List.of(values)),
-                                                        emptyList())))))))))))),
+                                                        List.of())))))))))))),
         explain.apply(plan));
   }
 
@@ -217,7 +215,7 @@ void can_explain_limit() {
             new ExplainResponseNode(
                 "LimitOperator",
                 Map.of("limit", 10, "offset", 5),
-                singletonList(tableScan.explainNode()))),
+                List.of(tableScan.explainNode()))),
         explain.apply(plan));
   }
 
@@ -237,7 +235,7 @@ void can_explain_takeOrdered() {
                     5,
                     "sortList",
                     Map.of("a", Map.of("sortOrder", "ASC", "nullOrder", "NULL_FIRST"))),
-                singletonList(tableScan.explainNode()))),
+                List.of(tableScan.explainNode()))),
         explain.apply(plan));
   }
 
@@ -252,7 +250,7 @@ void can_explain_nested() {
             new ExplainResponseNode(
                 "NestedOperator",
                 Map.of("nested", Set.of("message.info", "message")),
-                singletonList(tableScan.explainNode()))),
+                List.of(tableScan.explainNode()))),
         explain.apply(plan));
   }
 
@@ -275,7 +273,7 @@ public String toString() {
     /** Used to ignore table scan which is duplicate but required for each operator test. */
     public ExplainResponseNode explainNode() {
       return new ExplainResponseNode(
-          "FakeTableScan", Map.of("request", "Fake DSL request"), emptyList());
+          "FakeTableScan", Map.of("request", "Fake DSL request"), List.of());
     }
 
     public String explain() {
diff --git a/legacy/src/main/java/org/opensearch/sql/legacy/executor/format/DeleteResultSet.java b/legacy/src/main/java/org/opensearch/sql/legacy/executor/format/DeleteResultSet.java
index 6d6b05a3e3..9cfe8c9ec7 100644
--- a/legacy/src/main/java/org/opensearch/sql/legacy/executor/format/DeleteResultSet.java
+++ b/legacy/src/main/java/org/opensearch/sql/legacy/executor/format/DeleteResultSet.java
@@ -5,9 +5,6 @@
 
 package org.opensearch.sql.legacy.executor.format;
 
-import static java.util.Collections.singletonList;
-import static java.util.Collections.singletonMap;
-
 import java.util.List;
 import java.util.Map;
 import org.opensearch.client.Client;
@@ -29,14 +26,14 @@ public DeleteResultSet(Client client, Delete query, Object queryResult) {
   }
 
   private List<Schema.Column> loadColumns() {
-    return singletonList(new Schema.Column(DELETED, null, Schema.Type.LONG));
+    return List.of(new Schema.Column(DELETED, null, Schema.Type.LONG));
   }
 
   private List<DataRows.Row> loadRows() {
-    return singletonList(new DataRows.Row(loadDeletedData()));
+    return List.of(new DataRows.Row(loadDeletedData()));
   }
 
   private Map<String, Object> loadDeletedData() {
-    return singletonMap(DELETED, ((BulkByScrollResponse) queryResult).getDeleted());
+    return Map.of(DELETED, ((BulkByScrollResponse) queryResult).getDeleted());
   }
 }
diff --git a/legacy/src/main/java/org/opensearch/sql/legacy/expression/core/builder/UnaryExpressionBuilder.java b/legacy/src/main/java/org/opensearch/sql/legacy/expression/core/builder/UnaryExpressionBuilder.java
index de726d7e19..d7682d7bf3 100644
--- a/legacy/src/main/java/org/opensearch/sql/legacy/expression/core/builder/UnaryExpressionBuilder.java
+++ b/legacy/src/main/java/org/opensearch/sql/legacy/expression/core/builder/UnaryExpressionBuilder.java
@@ -5,8 +5,6 @@
 
 package org.opensearch.sql.legacy.expression.core.builder;
 
-import static java.util.Collections.singletonList;
-
 import java.util.List;
 import lombok.RequiredArgsConstructor;
 import org.opensearch.sql.legacy.expression.core.Expression;
@@ -32,7 +30,7 @@ public Expression build(List<Expression> expressionList) {
     return new Expression() {
       @Override
       public ExprValue valueOf(BindingTuple tuple) {
-        return op.apply(singletonList(expression.valueOf(tuple)));
+        return op.apply(List.of(expression.valueOf(tuple)));
       }
 
       @Override
diff --git a/opensearch/src/test/java/org/opensearch/sql/opensearch/request/OpenSearchRequestBuilderTest.java b/opensearch/src/test/java/org/opensearch/sql/opensearch/request/OpenSearchRequestBuilderTest.java
index 1e6bb6b171..0d0b0c3e67 100644
--- a/opensearch/src/test/java/org/opensearch/sql/opensearch/request/OpenSearchRequestBuilderTest.java
+++ b/opensearch/src/test/java/org/opensearch/sql/opensearch/request/OpenSearchRequestBuilderTest.java
@@ -5,7 +5,6 @@
 
 package org.opensearch.sql.opensearch.request;
 
-import static java.util.Collections.singletonList;
 import static org.junit.Assert.*;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.mockito.Mockito.*;
@@ -349,7 +348,7 @@ void test_push_down_query() {
   void test_push_down_aggregation() {
     AggregationBuilder aggBuilder =
         AggregationBuilders.composite(
-            "composite_buckets", singletonList(new TermsValuesSourceBuilder("longA")));
+            "composite_buckets", List.of(new TermsValuesSourceBuilder("longA")));
     OpenSearchAggregationResponseParser responseParser =
         new CompositeAggregationParser(new SingleValueParser("AVG(intA)"));
     requestBuilder.pushDownAggregation(Pair.of(List.of(aggBuilder), responseParser));
@@ -368,7 +367,7 @@ void test_push_down_aggregation() {
   void test_push_down_percentile_aggregation() {
     AggregationBuilder aggBuilder =
         AggregationBuilders.composite(
-            "composite_buckets", singletonList(new TermsValuesSourceBuilder("longA")));
+            "composite_buckets", List.of(new TermsValuesSourceBuilder("longA")));
     OpenSearchAggregationResponseParser responseParser =
         new CompositeAggregationParser(new SinglePercentileParser("PERCENTILE(intA, 50)"));
     requestBuilder.pushDownAggregation(Pair.of(List.of(aggBuilder), responseParser));