diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 026715279..e3f749fac 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -21,7 +21,7 @@ jobs:
     needs: Get-CI-Image-Tag
     strategy:
       matrix:
-        java: [11, 17]
+        java: [11, 17, 21]
         os: [ubuntu-latest]
 
     name: Gradle Check Linux
@@ -55,7 +55,7 @@ jobs:
   Check-neural-search-windows:
     strategy:
       matrix:
-        java: [11, 17]
+        java: [11, 17, 21]
         os: [windows-latest]
 
     name: Gradle Check Windows
@@ -83,7 +83,7 @@ jobs:
     needs: Get-CI-Image-Tag
     strategy:
       matrix:
-        java: [11, 17]
+        java: [11, 17, 21]
         os: [ubuntu-latest]
 
     name: Pre-commit Linux
@@ -117,7 +117,7 @@ jobs:
   Precommit-neural-search-windows:
     strategy:
       matrix:
-        java: [11, 17]
+        java: [11, 17, 21]
         os: [windows-latest]
 
     name: Pre-commit Windows
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 00aa761e4..a4f962510 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,5 +21,6 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Infrastructure
 ### Documentation
 ### Maintenance
+- Added support for jdk-21 ([#500](https://github.com/opensearch-project/neural-search/pull/500)))
 ### Refactoring
 Deprecate the `max_token_score` field in `neural_sparse` query clause ([#478](https://github.com/opensearch-project/neural-search/pull/478))
diff --git a/build.gradle b/build.gradle
index dd2ab1dcf..47f5cec3a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -109,8 +109,8 @@ buildscript {
 
     dependencies {
         classpath "${opensearch_group}.gradle:build-tools:${opensearch_version}"
-        classpath "com.diffplug.spotless:spotless-plugin-gradle:5.6.1"
-        classpath "io.freefair.gradle:lombok-plugin:8.0.1"
+        classpath "com.diffplug.spotless:spotless-plugin-gradle:6.23.2"
+        classpath "io.freefair.gradle:lombok-plugin:8.4"
     }
 }
 
@@ -144,7 +144,7 @@ dependencies {
     zipArchive group: 'org.opensearch.plugin', name:'opensearch-ml-plugin', version: "${opensearch_build}"
     compileOnly fileTree(dir: knnJarDirectory, include: '*.jar')
     api group: 'org.opensearch', name:'opensearch-ml-client', version: "${opensearch_build}"
-    implementation group: 'org.apache.commons', name: 'commons-lang3', version: '3.10'
+    implementation group: 'org.apache.commons', name: 'commons-lang3', version: '3.14.0'
     // ml-common excluded reflection for runtime so we need to add it by ourselves.
     // https://github.com/opensearch-project/ml-commons/commit/464bfe34c66d7a729a00dd457f03587ea4e504d9
     // TODO: Remove following three lines of dependencies if ml-common include them in their jar
@@ -255,7 +255,7 @@ testClusters.integTest {
 
     // Increase heap size from default of 512mb to 1gb. When heap size is 512mb, our integ tests sporadically fail due
     // to ml-commons memory circuit breaker exception
-    jvmArgs("-Xms1g", "-Xmx1g")
+    jvmArgs("-Xms1g", "-Xmx4g")
 }
 
 // Remote Integration Tests
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index c1962a79e..7f93135c4 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 560c9869d..46671acb6 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,7 +1,8 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.1.1-bin.zip
+distributionSha256Sum=3e1af3ae886920c3ac87f7a91f816c0c7c436f276a6eefdb3da152100fef72ae
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.4-bin.zip
 networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionSha256Sum=e111cb9948407e26351227dabce49822fb88c37ee72f1d1582a69c68af2e702f