Implementing generic and regular version of same interface

Question

I wanted to create a class that extends AbstractMap<Integer,Integer> and implements org.apache.commons.collections.BidiMap. BidiMap extends java.util.Map (not generic). I've gotten completely confused on how Java handles classes that implement multiple versions of an interface. Seems like you're not allowed to do it unless you introduce a layer of indirection. Even this is not really consistent
public class A {
  public interface B<T> {public T a();}
  public interface C extends B {}
  public class D implements B<Integer> {public Integer a() {return 0;}}
  // Illegal
  public class E implements B<Integer>, C {public Integer a() {return 0;}}
  // why is this allowed?
  public class F extends D implements C {public Integer a() {return 0;}}
  public interface G<T> {public void a(T pArg);}
  public interface H extends G {public Object b();}
  public class I implements G<Integer> {public void a(Integer pInt) {}}
  // Illegal.  Huh?
  public class J extends I implements G {public Integer a() {return 0;}}
}Anyone care to enlighten me on how this works? Is there any way to accomplish the original goal (extending AbstractMap<Integer,Integer> and implementing BidiMap)?

Answer 1

I've gotten completely confused on how Java handles classes
that implement multiple versions of an interface.It doesn't handle classes that implement multiple versions of an interface.
why is this allowed?On my machine, it isn't.A.java:9: A.B cannot be inherited with different arguments: <> and <java.lang.Integer>
  public class F extends D implements C {public Integer a() {return 0;}}