Skip adding methods already provided by a superclass

src/main/java/org/openrewrite/java/migrate/AddMissingMethodImplementation.java

@@ -23,6 +23,7 @@
 import org.openrewrite.java.MethodMatcher;
 import org.openrewrite.java.search.UsesType;
 import org.openrewrite.java.tree.J;
+import org.openrewrite.java.tree.JavaType;
 import org.openrewrite.java.tree.TypeUtils;
 
 import static org.openrewrite.java.tree.J.ClassDeclaration.Kind.Type.Interface;
@@ -79,6 +80,14 @@ public J.ClassDeclaration visitClassDeclaration(J.ClassDeclaration cs, Execution
                     .anyMatch(methodDeclaration -> methodMatcher.matches(methodDeclaration, classDecl))) {
                 return classDecl;
             }
+            // If a superclass already provides the method, don't add it.
+            JavaType.FullyQualified supertype = classDecl.getType() != null ? classDecl.getType().getSupertype() : null;
+            while (supertype != null) {
+                if (supertype.getMethods().stream().anyMatch(methodMatcher::matches)) {
+                    return classDecl;
+                }
+                supertype = supertype.getSupertype();
+            }
 
             return classDecl.withBody(JavaTemplate.builder(methodTemplateString)
                     .build()

src/test/java/org/openrewrite/java/migrate/AddMissingMethodImplementationTest.java

@@ -133,4 +133,22 @@ protected void m1() {
         );
     }
 
+    @Test
+    void skipWhenSuperclassAlreadyHasMethod() {
+        //language=java
+        rewriteRun(
+          java(
+            """
+              interface I1 {}
+              class SuperClass implements I1 {
+                  public void m1() {
+                      System.out.println("m1 from super");
+                  }
+              }
+              class SubClass extends SuperClass {}
+              """
+          )
+        );
+    }
+
 }