diff --git a/common/src/test/java/org/opensearch/ml/common/TestHelper.java b/common/src/test/java/org/opensearch/ml/common/TestHelper.java
index e1c5c9d03d..baa40f9102 100644
--- a/common/src/test/java/org/opensearch/ml/common/TestHelper.java
+++ b/common/src/test/java/org/opensearch/ml/common/TestHelper.java
@@ -36,7 +36,7 @@ public static <T> void testParse(ToXContentObject obj, Function<XContentParser,
         if (wrapWithObject) {
             builder.endObject();
         }
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         testParseFromString(obj, jsonStr, function);
     }
 
diff --git a/common/src/test/java/org/opensearch/ml/common/dataframe/BooleanValueTest.java b/common/src/test/java/org/opensearch/ml/common/dataframe/BooleanValueTest.java
index 2770d09ba5..d1597ada6a 100644
--- a/common/src/test/java/org/opensearch/ml/common/dataframe/BooleanValueTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/dataframe/BooleanValueTest.java
@@ -6,7 +6,6 @@
 package org.opensearch.ml.common.dataframe;
 
 import org.junit.Test;
-import org.opensearch.common.Strings;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.core.xcontent.XContentBuilder;
@@ -33,7 +32,7 @@ public void testToXContent() throws IOException {
         value.toXContent(builder);
 
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"column_type\":\"BOOLEAN\",\"value\":true}", jsonStr);
     }
 }
diff --git a/common/src/test/java/org/opensearch/ml/common/dataframe/ColumnMetaTest.java b/common/src/test/java/org/opensearch/ml/common/dataframe/ColumnMetaTest.java
index 7f308097a0..95ec45a3ae 100644
--- a/common/src/test/java/org/opensearch/ml/common/dataframe/ColumnMetaTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/dataframe/ColumnMetaTest.java
@@ -4,12 +4,9 @@
  */
 
 package org.opensearch.ml.common.dataframe;
-
 import org.junit.Before;
 import org.junit.Test;
-import org.opensearch.core.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.core.xcontent.XContentBuilder;
@@ -56,7 +53,7 @@ public void testToXContent() throws IOException {
         columnMeta.toXContent(builder);
 
         assertNotNull(builder);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"name\":\"columnMetaName\",\"column_type\":\"STRING\"}", jsonStr);
     }
 
diff --git a/common/src/test/java/org/opensearch/ml/common/dataframe/DefaultDataFrameTest.java b/common/src/test/java/org/opensearch/ml/common/dataframe/DefaultDataFrameTest.java
index acaf2c7284..3721f9d7a8 100644
--- a/common/src/test/java/org/opensearch/ml/common/dataframe/DefaultDataFrameTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/dataframe/DefaultDataFrameTest.java
@@ -14,7 +14,6 @@
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.common.xcontent.XContentType;
@@ -233,7 +232,7 @@ public void testToXContent() throws IOException {
         builder.endObject();
 
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"column_metas\":[" +
              "{\"name\":\"c1\",\"column_type\":\"STRING\"}," +
              "{\"name\":\"c2\",\"column_type\":\"INTEGER\"}," +
diff --git a/common/src/test/java/org/opensearch/ml/common/dataframe/DoubleValueTest.java b/common/src/test/java/org/opensearch/ml/common/dataframe/DoubleValueTest.java
index 7a3c5f0a15..9f2e665d56 100644
--- a/common/src/test/java/org/opensearch/ml/common/dataframe/DoubleValueTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/dataframe/DoubleValueTest.java
@@ -8,7 +8,6 @@
 import java.io.IOException;
 
 import org.junit.Test;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.MediaTypeRegistry;
@@ -51,7 +50,7 @@ public void testToXContent() throws IOException {
         doubleValue.toXContent(builder);
 
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"column_type\":\"DOUBLE\",\"value\":5.0}", jsonStr);
     }
 }
diff --git a/common/src/test/java/org/opensearch/ml/common/dataframe/FloatValueTest.java b/common/src/test/java/org/opensearch/ml/common/dataframe/FloatValueTest.java
index db3648c8fa..c9e8e552d7 100644
--- a/common/src/test/java/org/opensearch/ml/common/dataframe/FloatValueTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/dataframe/FloatValueTest.java
@@ -6,7 +6,6 @@
 package org.opensearch.ml.common.dataframe;
 
 import org.junit.Test;
-import org.opensearch.common.Strings;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.core.xcontent.XContentBuilder;
@@ -34,7 +33,7 @@ public void testToXContent() throws IOException {
         floatValue.toXContent(builder);
 
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"column_type\":\"FLOAT\",\"value\":2.1}", jsonStr);
     }
 }
diff --git a/common/src/test/java/org/opensearch/ml/common/dataframe/IntValueTest.java b/common/src/test/java/org/opensearch/ml/common/dataframe/IntValueTest.java
index 5c25002fdb..3048e88767 100644
--- a/common/src/test/java/org/opensearch/ml/common/dataframe/IntValueTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/dataframe/IntValueTest.java
@@ -6,7 +6,6 @@
 package org.opensearch.ml.common.dataframe;
 
 import org.junit.Test;
-import org.opensearch.common.Strings;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.core.xcontent.XContentBuilder;
@@ -33,7 +32,7 @@ public void testToXContent() throws IOException {
         intValue.toXContent(builder);
 
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"column_type\":\"INTEGER\",\"value\":2}", jsonStr);
     }
 }
diff --git a/common/src/test/java/org/opensearch/ml/common/dataframe/LongValueTest.java b/common/src/test/java/org/opensearch/ml/common/dataframe/LongValueTest.java
index 11118b42e4..5cfbe8cf5e 100644
--- a/common/src/test/java/org/opensearch/ml/common/dataframe/LongValueTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/dataframe/LongValueTest.java
@@ -6,7 +6,6 @@
 package org.opensearch.ml.common.dataframe;
 
 import org.junit.Test;
-import org.opensearch.common.Strings;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.core.xcontent.XContentBuilder;
@@ -33,7 +32,7 @@ public void testToXContent() throws IOException {
         longValue.toXContent(builder);
 
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"column_type\":\"LONG\",\"value\":2}", jsonStr);
     }
 }
diff --git a/common/src/test/java/org/opensearch/ml/common/dataframe/NullValueTest.java b/common/src/test/java/org/opensearch/ml/common/dataframe/NullValueTest.java
index 4acffc4989..90021d29ad 100644
--- a/common/src/test/java/org/opensearch/ml/common/dataframe/NullValueTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/dataframe/NullValueTest.java
@@ -6,7 +6,6 @@
 package org.opensearch.ml.common.dataframe;
 
 import org.junit.Test;
-import org.opensearch.common.Strings;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.core.xcontent.ToXContent;
@@ -34,7 +33,7 @@ public void testToXContent() throws IOException {
         value.toXContent(builder, ToXContent.EMPTY_PARAMS);
 
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"column_type\":\"NULL\"}", jsonStr);
     }
 }
diff --git a/common/src/test/java/org/opensearch/ml/common/dataframe/RowTest.java b/common/src/test/java/org/opensearch/ml/common/dataframe/RowTest.java
index 01198c7531..c2947ca944 100644
--- a/common/src/test/java/org/opensearch/ml/common/dataframe/RowTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/dataframe/RowTest.java
@@ -13,7 +13,6 @@
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.MediaTypeRegistry;
@@ -137,7 +136,7 @@ public void testToXContent() throws IOException {
         row.toXContent(builder);
 
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
 
         assertEquals("{\"values\":[{\"column_type\":\"INTEGER\",\"value\":0}]}", jsonStr);
     }
diff --git a/common/src/test/java/org/opensearch/ml/common/dataframe/ShortValueTest.java b/common/src/test/java/org/opensearch/ml/common/dataframe/ShortValueTest.java
index 2fbc43bdfa..c6e5b5366d 100644
--- a/common/src/test/java/org/opensearch/ml/common/dataframe/ShortValueTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/dataframe/ShortValueTest.java
@@ -6,7 +6,6 @@
 package org.opensearch.ml.common.dataframe;
 
 import org.junit.Test;
-import org.opensearch.common.Strings;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.core.xcontent.XContentBuilder;
@@ -33,7 +32,7 @@ public void testToXContent() throws IOException {
         shortValue.toXContent(builder);
 
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"column_type\":\"SHORT\",\"value\":2}", jsonStr);
     }
 }
diff --git a/common/src/test/java/org/opensearch/ml/common/dataframe/StringValueTest.java b/common/src/test/java/org/opensearch/ml/common/dataframe/StringValueTest.java
index 3f2ac26889..944d1efd59 100644
--- a/common/src/test/java/org/opensearch/ml/common/dataframe/StringValueTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/dataframe/StringValueTest.java
@@ -6,7 +6,6 @@
 package org.opensearch.ml.common.dataframe;
 
 import org.junit.Test;
-import org.opensearch.common.Strings;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.core.xcontent.ToXContent;
@@ -38,7 +37,7 @@ public void testToXContent() throws IOException {
         value.toXContent(builder, ToXContent.EMPTY_PARAMS);
 
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"column_type\":\"STRING\",\"value\":\"str\"}", jsonStr);
     }
 }
diff --git a/common/src/test/java/org/opensearch/ml/common/input/MLInputTest.java b/common/src/test/java/org/opensearch/ml/common/input/MLInputTest.java
index 99533df552..e836de34b3 100644
--- a/common/src/test/java/org/opensearch/ml/common/input/MLInputTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/input/MLInputTest.java
@@ -151,7 +151,7 @@ private void testParse(FunctionName algorithm, MLInputDataset inputDataset, Stri
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         input.toXContent(builder, ToXContent.EMPTY_PARAMS);
         assertNotNull(builder);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals(expectedInputStr, jsonStr);
 
         XContentParser parser = XContentType.JSON.xContent()
diff --git a/common/src/test/java/org/opensearch/ml/common/input/execute/anomalylocalization/AnomalyLocalizationInputTests.java b/common/src/test/java/org/opensearch/ml/common/input/execute/anomalylocalization/AnomalyLocalizationInputTests.java
index 58469c56ab..34bff7c246 100644
--- a/common/src/test/java/org/opensearch/ml/common/input/execute/anomalylocalization/AnomalyLocalizationInputTests.java
+++ b/common/src/test/java/org/opensearch/ml/common/input/execute/anomalylocalization/AnomalyLocalizationInputTests.java
@@ -38,7 +38,7 @@ public void testXContentFullObject() throws Exception {
                                 Optional.of(QueryBuilders.matchAllQuery()));
                 XContentBuilder builder = XContentFactory.jsonBuilder();
                 builder = input.toXContent(builder, null);
-                String json = org.opensearch.common.Strings.toString(builder);
+                String json = builder.toString();
 
                 XContentParser parser = XContentType.JSON.xContent()
                                 .createParser(new NamedXContentRegistry(new SearchModule(Settings.EMPTY,
@@ -56,7 +56,7 @@ public void testXContentMissingAnomalyStartFilter() throws Exception {
                                 "@timestamp", 0L, 10L, 1L, 2, Optional.empty(), Optional.empty());
                 XContentBuilder builder = XContentFactory.jsonBuilder();
                 builder = input.toXContent(builder, null);
-                String json = org.opensearch.common.Strings.toString(builder);
+                String json = builder.toString();
 
                 XContentParser parser = XContentType.JSON.xContent()
                                 .createParser(new NamedXContentRegistry(new SearchModule(Settings.EMPTY,
diff --git a/common/src/test/java/org/opensearch/ml/common/input/nlp/TextDocsMLInputTest.java b/common/src/test/java/org/opensearch/ml/common/input/nlp/TextDocsMLInputTest.java
index d0e8fa583f..2722effce5 100644
--- a/common/src/test/java/org/opensearch/ml/common/input/nlp/TextDocsMLInputTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/input/nlp/TextDocsMLInputTest.java
@@ -50,7 +50,7 @@ public void setUp() throws Exception {
     public void parseTextDocsMLInput() throws IOException {
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         input.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         System.out.println(jsonStr);
         parseMLInput(jsonStr);
     }
diff --git a/common/src/test/java/org/opensearch/ml/common/output/MLPredictionOutputTest.java b/common/src/test/java/org/opensearch/ml/common/output/MLPredictionOutputTest.java
index 3f8637e261..612ea3c104 100644
--- a/common/src/test/java/org/opensearch/ml/common/output/MLPredictionOutputTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/output/MLPredictionOutputTest.java
@@ -51,7 +51,7 @@ public void setUp() {
     public void toXContent() throws IOException {
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         output.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"task_id\":\"test_task_id\",\"status\":\"test_status\",\"prediction_result\":" +
                 "{\"column_metas\":[{\"name\":\"test\",\"column_type\":\"INTEGER\"}],\"rows\":[{\"values\":" +
                 "[{\"column_type\":\"INTEGER\",\"value\":1}]},{\"values\":[{\"column_type\":\"INTEGER\"," +
@@ -63,7 +63,7 @@ public void toXContent_EmptyOutput() throws IOException {
         MLPredictionOutput output = MLPredictionOutput.builder().build();
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         output.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{}", jsonStr);
     }
 
diff --git a/common/src/test/java/org/opensearch/ml/common/output/MLTrainingOutputTest.java b/common/src/test/java/org/opensearch/ml/common/output/MLTrainingOutputTest.java
index d21afd9115..01b997adfa 100644
--- a/common/src/test/java/org/opensearch/ml/common/output/MLTrainingOutputTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/output/MLTrainingOutputTest.java
@@ -6,8 +6,6 @@
 package org.opensearch.ml.common.output;
 
 import org.junit.Test;
-import org.opensearch.common.Strings;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.core.xcontent.ToXContent;
@@ -24,7 +22,7 @@ public void parse_MLTrain() throws IOException {
                 .modelId("test_modelId").status("test_status").build();
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         output.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"model_id\":\"test_modelId\",\"status\":\"test_status\"}", jsonStr);
     }
 }
diff --git a/common/src/test/java/org/opensearch/ml/common/output/execute/anomalylocalization/AnomalyLocalizationOutputTests.java b/common/src/test/java/org/opensearch/ml/common/output/execute/anomalylocalization/AnomalyLocalizationOutputTests.java
index 65e9fb8c75..d14508ea43 100644
--- a/common/src/test/java/org/opensearch/ml/common/output/execute/anomalylocalization/AnomalyLocalizationOutputTests.java
+++ b/common/src/test/java/org/opensearch/ml/common/output/execute/anomalylocalization/AnomalyLocalizationOutputTests.java
@@ -9,7 +9,6 @@
 
 import org.junit.Before;
 import org.junit.Test;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentType;
@@ -51,7 +50,7 @@ public void testXContent() throws Exception {
         builder.startObject();
         builder = output.toXContent(builder, null);
         builder.endObject();
-        String json = Strings.toString(builder);
+        String json = builder.toString();
         XContentParser parser = XContentType.JSON.xContent().createParser(NamedXContentRegistry.EMPTY, null, json);
         AnomalyLocalizationOutput newOutput = AnomalyLocalizationOutput.parse(parser);
 
diff --git a/common/src/test/java/org/opensearch/ml/common/output/execute/samplecalculator/LocalSampleCalculatorOutputTest.java b/common/src/test/java/org/opensearch/ml/common/output/execute/samplecalculator/LocalSampleCalculatorOutputTest.java
index 49f05e4dae..c3c7a71da7 100644
--- a/common/src/test/java/org/opensearch/ml/common/output/execute/samplecalculator/LocalSampleCalculatorOutputTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/output/execute/samplecalculator/LocalSampleCalculatorOutputTest.java
@@ -37,7 +37,7 @@ public void toXContent() throws IOException {
         builder.startObject();
         output.toXContent(builder, ToXContent.EMPTY_PARAMS);
         builder.endObject();
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"result\":1.0}", jsonStr);
     }
 
@@ -48,7 +48,7 @@ public void toXContent_EmptyOutput() throws IOException {
         builder.startObject();
         output.toXContent(builder, ToXContent.EMPTY_PARAMS);
         builder.endObject();
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{}", jsonStr);
     }
 
diff --git a/common/src/test/java/org/opensearch/ml/common/output/sample/SampleAlgoOutputTest.java b/common/src/test/java/org/opensearch/ml/common/output/sample/SampleAlgoOutputTest.java
index a1ddb7e7b2..c417758058 100644
--- a/common/src/test/java/org/opensearch/ml/common/output/sample/SampleAlgoOutputTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/output/sample/SampleAlgoOutputTest.java
@@ -35,7 +35,7 @@ public void setUp() {
     public void toXContent() throws IOException {
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         output.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"sample_result\":1.0}", jsonStr);
     }
 
@@ -44,7 +44,7 @@ public void toXContent_EmptyOutput() throws IOException {
         SampleAlgoOutput output = SampleAlgoOutput.builder().build();
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         output.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{}", jsonStr);
     }
 
diff --git a/common/src/test/java/org/opensearch/ml/common/transport/deploy/MLDeployModelNodesResponseTest.java b/common/src/test/java/org/opensearch/ml/common/transport/deploy/MLDeployModelNodesResponseTest.java
index 447a647a79..c7bd1dcc3a 100644
--- a/common/src/test/java/org/opensearch/ml/common/transport/deploy/MLDeployModelNodesResponseTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/transport/deploy/MLDeployModelNodesResponseTest.java
@@ -75,7 +75,7 @@ public void testToXContent() throws IOException {
         MLDeployModelNodesResponse response = new MLDeployModelNodesResponse(clusterName, nodes, failures);
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         response.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals(
                 "{\"foo1\":{\"stats\":{\"modelName:version1\":\"response\"}},\"foo2\":{\"stats\":{\"modelName:version2\":\"response\"}}}",
                 jsonStr);
diff --git a/common/src/test/java/org/opensearch/ml/common/transport/deploy/MLDeployModelResponseTest.java b/common/src/test/java/org/opensearch/ml/common/transport/deploy/MLDeployModelResponseTest.java
index ba4ef87033..854af206c6 100644
--- a/common/src/test/java/org/opensearch/ml/common/transport/deploy/MLDeployModelResponseTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/transport/deploy/MLDeployModelResponseTest.java
@@ -47,7 +47,7 @@ public void testToXContent() throws IOException {
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         response.toXContent(builder, ToXContent.EMPTY_PARAMS);
         assertNotNull(builder);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         // Verify the results
         assertEquals("{\"task_id\":\"test_id\"," +
                 "\"status\":\"test\"}", jsonStr);
diff --git a/common/src/test/java/org/opensearch/ml/common/transport/execute/MLExecuteTaskResponseTest.java b/common/src/test/java/org/opensearch/ml/common/transport/execute/MLExecuteTaskResponseTest.java
index e77a90c9c9..1dfc5f29cd 100644
--- a/common/src/test/java/org/opensearch/ml/common/transport/execute/MLExecuteTaskResponseTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/transport/execute/MLExecuteTaskResponseTest.java
@@ -1,7 +1,6 @@
 package org.opensearch.ml.common.transport.execute;
 
 import org.junit.Test;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentType;
@@ -91,7 +90,7 @@ public void toXContentTest() throws IOException {
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         response.toXContent(builder, ToXContent.EMPTY_PARAMS);
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"function_name\":\"METRICS_CORRELATION\"," +
                 "\"output\":{\"inference_results\":[{" +
                 "\"event_window\":[4.0,5.0,6.0]," +
diff --git a/common/src/test/java/org/opensearch/ml/common/transport/forward/MLForwardResponseTest.java b/common/src/test/java/org/opensearch/ml/common/transport/forward/MLForwardResponseTest.java
index aebe33e153..df4f415722 100644
--- a/common/src/test/java/org/opensearch/ml/common/transport/forward/MLForwardResponseTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/transport/forward/MLForwardResponseTest.java
@@ -66,7 +66,7 @@ public void testToXContent() throws IOException {
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         response.toXContent(builder, ToXContent.EMPTY_PARAMS);
         assertNotNull(builder);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         // Verify the results
         assertEquals(
                 "{\"result\":{\"task_id\":\"taskId\",\"status\":\"Success\",\"prediction_result\":{\"column_metas\":[{\"name\":\"key1\",\"column_type\":\"DOUBLE\"}],\"rows\":[{\"values\":[{\"column_type\":\"DOUBLE\",\"value\":2.0}]}]}}}",
diff --git a/common/src/test/java/org/opensearch/ml/common/transport/model/MLModelGetResponseTest.java b/common/src/test/java/org/opensearch/ml/common/transport/model/MLModelGetResponseTest.java
index 62f336281d..fc957f0dbe 100644
--- a/common/src/test/java/org/opensearch/ml/common/transport/model/MLModelGetResponseTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/transport/model/MLModelGetResponseTest.java
@@ -59,7 +59,7 @@ public void toXContentTest() throws IOException {
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         mlModelGetResponse.toXContent(builder, ToXContent.EMPTY_PARAMS);
         assertNotNull(builder);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"name\":\"model\"," +
                 "\"algorithm\":\"KMEANS\"," +
                 "\"model_version\":\"1.0.0\"," +
diff --git a/common/src/test/java/org/opensearch/ml/common/transport/prediction/MLPredictionTaskResponseTest.java b/common/src/test/java/org/opensearch/ml/common/transport/prediction/MLPredictionTaskResponseTest.java
index 0622183fb8..9eb8532044 100644
--- a/common/src/test/java/org/opensearch/ml/common/transport/prediction/MLPredictionTaskResponseTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/transport/prediction/MLPredictionTaskResponseTest.java
@@ -128,7 +128,7 @@ public void toXContentTest() throws IOException {
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         response.toXContent(builder, ToXContent.EMPTY_PARAMS);
         assertNotNull(builder);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"task_id\":\"b5009b99-268f-476d-a676-379a30f82457\"," +
                 "\"status\":\"Success\"," +
                 "\"prediction_result\":{" +
diff --git a/common/src/test/java/org/opensearch/ml/common/transport/register/MLRegisterModelInputTest.java b/common/src/test/java/org/opensearch/ml/common/transport/register/MLRegisterModelInputTest.java
index 4f4e45bb73..6a3b554c31 100644
--- a/common/src/test/java/org/opensearch/ml/common/transport/register/MLRegisterModelInputTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/transport/register/MLRegisterModelInputTest.java
@@ -7,7 +7,6 @@
 import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.junit.MockitoJUnitRunner;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
@@ -147,7 +146,7 @@ public void testToXContent() throws Exception {
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         input.toXContent(builder, ToXContent.EMPTY_PARAMS);
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals(expectedInputStr, jsonStr);
     }
 
@@ -163,7 +162,7 @@ public void testToXContent_Incomplete() throws Exception {
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         input.toXContent(builder, ToXContent.EMPTY_PARAMS);
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals(expectedIncompleteInputStr, jsonStr);
     }
 
diff --git a/common/src/test/java/org/opensearch/ml/common/transport/register/MLRegisterModelResponseTest.java b/common/src/test/java/org/opensearch/ml/common/transport/register/MLRegisterModelResponseTest.java
index 13e1a3bb78..b658667f50 100644
--- a/common/src/test/java/org/opensearch/ml/common/transport/register/MLRegisterModelResponseTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/transport/register/MLRegisterModelResponseTest.java
@@ -47,7 +47,7 @@ public void testToXContent() throws IOException {
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         response.toXContent(builder, ToXContent.EMPTY_PARAMS);
         assertNotNull(builder);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         // Verify the results
         assertEquals("{\"task_id\":\"test_id\"," +
                 "\"status\":\"test\"}", jsonStr);
diff --git a/common/src/test/java/org/opensearch/ml/common/transport/sync/MLSyncUpResponseTest.java b/common/src/test/java/org/opensearch/ml/common/transport/sync/MLSyncUpResponseTest.java
index da13327fc5..19f6f6a7d6 100644
--- a/common/src/test/java/org/opensearch/ml/common/transport/sync/MLSyncUpResponseTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/transport/sync/MLSyncUpResponseTest.java
@@ -46,7 +46,7 @@ public void testToXContent() throws IOException {
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         response.toXContent(builder, ToXContent.EMPTY_PARAMS);
         assertNotNull(builder);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         // Verify the results
         assertEquals("{\"status\":\"test\"}", jsonStr);
     }
diff --git a/common/src/test/java/org/opensearch/ml/common/transport/task/MLTaskGetResponseTest.java b/common/src/test/java/org/opensearch/ml/common/transport/task/MLTaskGetResponseTest.java
index 007082d96e..ba4d8d7d95 100644
--- a/common/src/test/java/org/opensearch/ml/common/transport/task/MLTaskGetResponseTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/transport/task/MLTaskGetResponseTest.java
@@ -2,9 +2,7 @@
 
 import org.junit.Before;
 import org.junit.Test;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.commons.authuser.User;
 import org.opensearch.core.xcontent.MediaTypeRegistry;
@@ -73,7 +71,7 @@ public void toXContentTest() throws IOException {
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         mlTaskGetResponse.toXContent(builder, ToXContent.EMPTY_PARAMS);
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals("{\"task_id\":\"id\"," +
                 "\"model_id\":\"model id\"," +
                 "\"task_type\":\"EXECUTION\"," +
diff --git a/common/src/test/java/org/opensearch/ml/common/transport/undeploy/MLUndeployModelInputTest.java b/common/src/test/java/org/opensearch/ml/common/transport/undeploy/MLUndeployModelInputTest.java
index db5dd965f6..c76e73afe9 100644
--- a/common/src/test/java/org/opensearch/ml/common/transport/undeploy/MLUndeployModelInputTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/transport/undeploy/MLUndeployModelInputTest.java
@@ -2,7 +2,6 @@
 
 import org.junit.Before;
 import org.junit.Test;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
@@ -39,7 +38,7 @@ public void testToXContent() throws Exception {
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         input.toXContent(builder, ToXContent.EMPTY_PARAMS);
         assertNotNull(builder);
-        String jsonStr = Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals(expectedInputStr, jsonStr);
     }
 
diff --git a/common/src/test/java/org/opensearch/ml/common/transport/undeploy/MLUndeployModelNodesResponseTest.java b/common/src/test/java/org/opensearch/ml/common/transport/undeploy/MLUndeployModelNodesResponseTest.java
index 484d193123..d80c269679 100644
--- a/common/src/test/java/org/opensearch/ml/common/transport/undeploy/MLUndeployModelNodesResponseTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/transport/undeploy/MLUndeployModelNodesResponseTest.java
@@ -91,7 +91,7 @@ public void testToXContent() throws IOException {
         MLUndeployModelNodesResponse response = new MLUndeployModelNodesResponse(clusterName, nodes, failures);
         XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         response.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         assertEquals(
                 "{\"foo1\":{\"stats\":{\"modelId1\":\"response\"}},\"foo2\":{\"stats\":{\"modelId2\":\"response\"}}}",
                 jsonStr);
diff --git a/common/src/test/java/org/opensearch/ml/common/transport/upload_chunk/MLUploadModelChunkInputTest.java b/common/src/test/java/org/opensearch/ml/common/transport/upload_chunk/MLUploadModelChunkInputTest.java
index 9acbcef6ef..cafec77356 100644
--- a/common/src/test/java/org/opensearch/ml/common/transport/upload_chunk/MLUploadModelChunkInputTest.java
+++ b/common/src/test/java/org/opensearch/ml/common/transport/upload_chunk/MLUploadModelChunkInputTest.java
@@ -15,7 +15,6 @@
 
 import org.junit.Before;
 import org.junit.Test;
-import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.common.settings.Settings;
@@ -90,7 +89,7 @@ public void testToXContent() throws IOException {
 	public void testMLUploadModelChunkInputParser() throws IOException {
 		XContentBuilder builder = XContentFactory.jsonBuilder();
 		builder = mlUploadModelChunkInput.toXContent(builder, null);
-		String json = Strings.toString(builder);
+		String json = builder.toString();
 		XContentParser parser = XContentType.JSON.xContent().createParser(new NamedXContentRegistry(
 				new SearchModule(Settings.EMPTY, Collections.emptyList()).getNamedXContents()), null, json);
 		parser.nextToken();
diff --git a/plugin/src/main/java/org/opensearch/ml/utils/MLExceptionUtils.java b/plugin/src/main/java/org/opensearch/ml/utils/MLExceptionUtils.java
index de2c713d5e..e59e2ee0fe 100644
--- a/plugin/src/main/java/org/opensearch/ml/utils/MLExceptionUtils.java
+++ b/plugin/src/main/java/org/opensearch/ml/utils/MLExceptionUtils.java
@@ -10,7 +10,6 @@
 
 import org.apache.commons.lang3.exception.ExceptionUtils;
 import org.apache.logging.log4j.Logger;
-import org.opensearch.common.Strings;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.ml.common.exception.MLLimitExceededException;
@@ -39,7 +38,7 @@ public static String toJsonString(Map<String, String> nodeErrors) throws IOExcep
             builder.field(entry.getKey(), entry.getValue());
         }
         builder.endObject();
-        return Strings.toString(builder);
+        return builder.toString();
     }
 
     public static void logException(String errorMessage, Exception e, Logger log) {
diff --git a/plugin/src/test/java/org/opensearch/ml/utils/IntegTestUtils.java b/plugin/src/test/java/org/opensearch/ml/utils/IntegTestUtils.java
index c97994c5be..511cad9655 100644
--- a/plugin/src/test/java/org/opensearch/ml/utils/IntegTestUtils.java
+++ b/plugin/src/test/java/org/opensearch/ml/utils/IntegTestUtils.java
@@ -196,7 +196,7 @@ public static void predictAndVerifyResult(String taskId, MLInputDataset inputDat
         MLPredictionOutput mlPredictionOutput = (MLPredictionOutput) predictionResponse.getOutput();
         mlPredictionOutput.getPredictionResult().toXContent(builder, ToXContent.EMPTY_PARAMS);
         builder.endObject();
-        String jsonStr = org.opensearch.common.Strings.toString(builder);
+        String jsonStr = builder.toString();
         String expectedStr1 = "{\"column_metas\":[{\"name\":\"ClusterID\",\"column_type\":\"INTEGER\"}],"
             + "\"rows\":[{\"values\":[{\"column_type\":\"INTEGER\",\"value\":0}]}]}";
         String expectedStr2 = "{\"column_metas\":[{\"name\":\"ClusterID\",\"column_type\":\"INTEGER\"}],"