Description Arvid Heise 2007-08-20 09:27:07 EDT

This bug seems closely related to https://bugs.eclipse.org/bugs/show_bug.cgi?id=100869.

If you extend the example through a second bound, the JDT would issue the error when invoking the method m:
The method m(Integer) is ambiguous for the type B.

javac 1.6.0 compiles it without errors or warnings. Note that the @Override annotation does not result in any warning or error in the JDT.

If you remove any of these two bounds or if A becomes an interface, the error would disappear. This error remains if A provides an implementation for m.

abstract class A {
    abstract <T extends Number & Comparable<T>> void m(T x);
}

class B extends A {
    @Override
    <T extends Number & Comparable<T>> void m(T x) {}
}

class C {
    public static void main(String[] args) {
        new B().m(new Integer(1));
    }
}