delegate: don't copy override as it would be added explicitly (IDEA-178893)

java/java-impl/src/com/intellij/codeInsight/generation/GenerateDelegateHandler.java

@@ -163,7 +163,8 @@ public class GenerateDelegateHandler implements LanguageCodeInsightActionHandler
     stmt = (PsiStatement)CodeStyleManager.getInstance(psiManager.getProject()).reformat(stmt);
     method.getBody().add(stmt);
 
-    GenerateMembersUtil.copyAnnotations(methodCandidate.getElement().getModifierList(), method.getModifierList(), SuppressWarnings.class.getName());
+    GenerateMembersUtil.copyAnnotations(methodCandidate.getElement().getModifierList(), method.getModifierList(), 
+                                        SuppressWarnings.class.getName(), Override.class.getName());
 
     if (isMethodStatic || modifierList != null && modifierList.hasModifierProperty(PsiModifier.STATIC)) {
       PsiUtil.setModifierProperty(method, PsiModifier.STATIC, true);

java/java-tests/testData/codeInsight/delegateMethods/afterEnsureCorrectOverride.java

@@ -0,0 +1,17 @@
+interface I {
+  void foo();
+}
+class A implements I {
+  @Override
+  public void foo() {
+    
+  }
+}
+
+class B {
+  A a;
+
+    public void foo() {
+        a.foo();
+    }
+}

java/java-tests/testData/codeInsight/delegateMethods/beforeEnsureCorrectOverride.java

@@ -0,0 +1,14 @@
+interface I {
+  void foo();
+}
+class A implements I {
+  @Override
+  public void foo() {
+    
+  }
+}
+
+class B {
+  A a;
+  <caret>
+}

java/java-tests/testSrc/com/intellij/java/codeInsight/DelegateMethodsTest.java

@@ -58,6 +58,7 @@ public class DelegateMethodsTest extends LightCodeInsightTestCase {
   public void testMultipleOverrideAnnotations() { doTest(); }
   public void testStripSuppressWarningsAnnotation() { doTest(); }
   public void testDoNotOverrideFinal() { doTest(); }
+  public void testEnsureCorrectOverride() { doTest(); }
   public void testAllowDelegateToFinal() { doTest(); }
   public void testDelegateWithSubstitutionOverrides() { doTest(); }
   public void testDelegateWithSubstitutionNoOverrides() { doTest(); }