Description Rémi Forax 2006-03-22 10:18:21 EST

The following code generate an AbstractMethodError at runtime :

----------------------------------------------------------------
import java.util.List;

public interface I<T> {
  List<T> f(T t);
}
----------------------------------------------------------------
import java.util.List;
public abstract class A<N extends A.NImpl> implements I<N> {
  public List<N> f(NImpl n) { // <--- oh oh, little trick
    return null;
  }
  
  static class NImpl {
  }
}
------------------------------------------------------------
public class B extends A<A.NImpl> {
}
------------------------------------------------------------
import java.util.List;

public class Test {
  public static <T> List<T> f(I<T> i,T t) {
    return i.f(t);
  }
  public static void main(String[] args) {
    I<?> i=new B();
    i.f(null);
  }
}

at runtime :
Exception in thread "main" java.lang.AbstractMethodError: bug2.B.f(Ljava/lang/Object;)Ljava/util/List;
	at bug2.Test.main(Test.java:11)

the bridge b.f() in not generated by eclipse compiler.

Rémi Forax