diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 84b4f09f9..c807e348e 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -20,7 +20,7 @@ jobs:
   Build-k-NN-Linux:
     strategy:
       matrix:
-        java: [11, 17]
+        java: [11, 17, 21]
 
     name: Build and Test k-NN Plugin on Linux
     runs-on: ubuntu-latest
@@ -57,7 +57,7 @@ jobs:
   Build-k-NN-MacOS:
     strategy:
       matrix:
-        java: [ 11, 17 ]
+        java: [ 11, 17, 21 ]
 
     name: Build and Test k-NN Plugin on MacOS
     needs: Get-CI-Image-Tag
@@ -84,7 +84,7 @@ jobs:
   Build-k-NN-Windows:
     strategy:
       matrix:
-        java: [ 11, 17 ]
+        java: [ 11, 17, 21 ]
 
     name: Build and Test k-NN Plugin on Windows
     needs: Get-CI-Image-Tag
diff --git a/.github/workflows/test_security.yml b/.github/workflows/test_security.yml
index 3813ff675..ff3ca1459 100644
--- a/.github/workflows/test_security.yml
+++ b/.github/workflows/test_security.yml
@@ -15,7 +15,7 @@ jobs:
   Build-ad:
     strategy:
       matrix:
-        java: [ 11,17 ]
+        java: [ 11,17,21 ]
         os: [ubuntu-latest]
       fail-fast: true
 
diff --git a/build.gradle b/build.gradle
index f3dcff3e3..fb56692ce 100644
--- a/build.gradle
+++ b/build.gradle
@@ -36,7 +36,7 @@ plugins {
     id 'java-library'
     id 'java-test-fixtures'
     id 'idea'
-    id "com.diffplug.spotless" version "6.3.0" apply false
+    id "com.diffplug.spotless" version "6.20.0" apply false
     id 'io.freefair.lombok' version '8.4'
 }
 
diff --git a/src/main/java/org/opensearch/knn/indices/ModelDao.java b/src/main/java/org/opensearch/knn/indices/ModelDao.java
index fe0deb1cf..eada08b44 100644
--- a/src/main/java/org/opensearch/knn/indices/ModelDao.java
+++ b/src/main/java/org/opensearch/knn/indices/ModelDao.java
@@ -654,7 +654,9 @@ private void removeModelIdFromGraveyardOnFailure(String modelId, Exception excep
             client.execute(
                 UpdateModelGraveyardAction.INSTANCE,
                 new UpdateModelGraveyardRequest(modelId, true),
-                ActionListener.wrap(acknowledgedResponse -> { throw exceptionFromPreviousStep; }, unblockingFailedException -> {
+                ActionListener.wrap(acknowledgedResponse -> {
+                    throw exceptionFromPreviousStep;
+                }, unblockingFailedException -> {
                     // If it fails to remove the modelId from Model Graveyard, then log the error message and
                     // throw the exception that was passed as a parameter from previous step
                     String errorMessage = String.format("Failed to remove \" %s \" from Model Graveyard", modelId);
diff --git a/src/main/java/org/opensearch/knn/plugin/transport/KNNWarmupResponse.java b/src/main/java/org/opensearch/knn/plugin/transport/KNNWarmupResponse.java
index f13fbd3db..d9e607db2 100644
--- a/src/main/java/org/opensearch/knn/plugin/transport/KNNWarmupResponse.java
+++ b/src/main/java/org/opensearch/knn/plugin/transport/KNNWarmupResponse.java
@@ -5,7 +5,7 @@
 
 package org.opensearch.knn.plugin.transport;
 
-import org.opensearch.core.action.support.DefaultShardOperationFailedException;;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.BroadcastResponse;
 import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.core.xcontent.ToXContentObject;
diff --git a/src/main/java/org/opensearch/knn/plugin/transport/KNNWarmupTransportAction.java b/src/main/java/org/opensearch/knn/plugin/transport/KNNWarmupTransportAction.java
index c55c9b619..a738527ff 100644
--- a/src/main/java/org/opensearch/knn/plugin/transport/KNNWarmupTransportAction.java
+++ b/src/main/java/org/opensearch/knn/plugin/transport/KNNWarmupTransportAction.java
@@ -9,7 +9,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.action.support.ActionFilters;
-import org.opensearch.core.action.support.DefaultShardOperationFailedException;;
+import org.opensearch.core.action.support.DefaultShardOperationFailedException;
 import org.opensearch.action.support.broadcast.node.TransportBroadcastByNodeAction;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.block.ClusterBlockException;
diff --git a/src/testFixtures/java/org/opensearch/knn/TestUtils.java b/src/testFixtures/java/org/opensearch/knn/TestUtils.java
index a9721ce14..61c0abe4f 100644
--- a/src/testFixtures/java/org/opensearch/knn/TestUtils.java
+++ b/src/testFixtures/java/org/opensearch/knn/TestUtils.java
@@ -208,12 +208,9 @@ public static PriorityQueue<DistVector> computeGroundTruthValues(int k, SpaceTyp
     public static float computeDistFromSpaceType(SpaceType spaceType, float[] indexVector, float[] queryVector) {
         float dist;
         if (spaceType != null) {
-            dist = KNN_SCORING_SPACE_TYPE.getOrDefault(
-                spaceType,
-                (defaultQueryVector, defaultIndexVector) -> {
-                    throw new IllegalArgumentException(String.format("Invalid SpaceType function: \"%s\"", spaceType));
-                }
-            ).apply(queryVector, indexVector);
+            dist = KNN_SCORING_SPACE_TYPE.getOrDefault(spaceType, (defaultQueryVector, defaultIndexVector) -> {
+                throw new IllegalArgumentException(String.format("Invalid SpaceType function: \"%s\"", spaceType));
+            }).apply(queryVector, indexVector);
         } else {
             throw new NullPointerException("SpaceType is null. Provide a valid SpaceType.");
         }