SUBMARINE-1349. Fix the syntax error reported in sonarcloud and add init value for apiversion in XGboostjobList.java

Author: hhcs9527

submarine-server/server-core/src/main/java/org/apache/submarine/server/manager/ModelVersionManager.java

@@ -50,14 +50,10 @@ public class ModelVersionManager {
    *
    * @return object
    */
-  public static ModelVersionManager getInstance() {
+  public static synchronized ModelVersionManager getInstance() {
     if (manager == null) {
-      synchronized (ModelVersionManager.class) {
-        if (manager == null) {
-          manager = new ModelVersionManager(new ModelVersionService(), new ModelVersionTagService(),
-            new Client());
-        }
-      }
+      manager = new ModelVersionManager(new ModelVersionService(), new ModelVersionTagService(),
+          new Client());
     }
     return manager;
   }

submarine-server/server-core/src/main/java/org/apache/submarine/server/manager/RegisteredModelManager.java

@@ -54,14 +54,10 @@ public class RegisteredModelManager {
    *
    * @return object
    */
-  public static RegisteredModelManager getInstance() {
+  public static synchronized RegisteredModelManager getInstance() {
     if (manager == null) {
-      synchronized (RegisteredModelManager.class) {
-        if (manager == null) {
-          manager = new RegisteredModelManager(new RegisteredModelService(), new ModelVersionService(),
-              new RegisteredModelTagService(), new Client());
-        }
-      }
+      manager = new RegisteredModelManager(new RegisteredModelService(), new ModelVersionService(),
+          new RegisteredModelTagService(), new Client());
     }
     return manager;
   }

submarine-server/server-submitter/submitter-k8s/src/main/java/org/apache/submarine/server/submitter/k8s/model/xgboostjob/XGBoostJobList.java

@@ -27,7 +27,7 @@
 
 public class XGBoostJobList implements KubernetesListObject {
   @SerializedName("apiVersion")
-  private String apiVersion;
+  private String apiVersion = XGBoostJob.CRD_XGBOOST_API_VERSION_V1;
 
   @SerializedName("kind")
   private String kind;