diff --git a/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2024-01-01-preview/appplatform.json b/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2024-01-01-preview/appplatform.json
index 198cfeebafc4..cd28f46c6565 100644
--- a/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2024-01-01-preview/appplatform.json
+++ b/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2024-01-01-preview/appplatform.json
@@ -13383,6 +13383,7 @@
             "Java_8",
             "Java_11",
             "Java_17",
+            "Java_21",
             "NetCore_31"
           ],
           "type": "string",
diff --git a/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2024-01-01-preview/examples/RuntimeVersions_ListRuntimeVersions.json b/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2024-01-01-preview/examples/RuntimeVersions_ListRuntimeVersions.json
index ab984ce84a66..4f499b061626 100644
--- a/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2024-01-01-preview/examples/RuntimeVersions_ListRuntimeVersions.json
+++ b/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2024-01-01-preview/examples/RuntimeVersions_ListRuntimeVersions.json
@@ -21,6 +21,11 @@
             "platform": "Java",
             "version": "17"
           },
+          {
+            "value": "Java_21",
+            "platform": "Java",
+            "version": "21"
+          },
           {
             "value": "NetCore_31",
             "platform": ".NET Core",