JDK-4972073 : (compound) same interface allowed twice in compound type
  • Type: Bug
  • Component: tools
  • Sub-Component: javac
  • Affected Version: 5.0
  • Priority: P4
  • Status: Closed
  • Resolution: Fixed
  • OS: solaris_9
  • CPU: sparc
  • Submitted: 2003-12-23
  • Updated: 2017-05-16
  • Resolved: 2011-03-08
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7 b03Fixed
generic class signature allows to extends the same interface multiple times.
Ideally it should throw compile time here. 

Please find the below code. It compiles successfully. But I think it shouldn't compile it. Class B signature allows to extends the MyInterface<E> twice.

//-- Code start here --
import java.lang.reflect.*;

public class Test1 {
	public static void main(String[] args) {
		B b = new B<Sun1>();

class D { }

interface MyInterface<E> {
	public String foo();

class MyClass { }

class Sun1 extends MyClass implements MyInterface<Sun1>, MyInterface<Sun1> {
	public String foo() {
		return "test";

class B < E extends MyClass & MyInterface<E> & MyInterface<E> > extends D {
//-- code end here


CONVERTED DATA BugTraq+ Release Management Values COMMIT TO FIX: dragon mustang

PUBLIC COMMENTS This program compiles, but I<E> is repeated in the bound of E: interface I<X> {} class C<E extends I<E> & I<E>> {} ###@###.### 2004-09-06

EVALUATION Looks like a bug ###@###.### 2004-01-06