Description Martin Nilsson 2009-11-03 08:45:51 EST

I'm running into a problem with an API that I'm developing that deals with generics and inner interfaces. A very simple example of the problem is the following:

SuperInterface.java:

package com.test.superint;

public interface SuperInterface<G extends SuperInterface.SuperInterfaceGetter, S extends SuperInterface.SuperInterfaceSetter> {
    public interface SuperInterfaceGetter {}

    public interface SuperInterfaceSetter {}
}

SubInterface.java:

package com.test.subint;

import com.test.superint.SuperInterface;

public interface SubInterface extends SuperInterface<SubInterface.SubInterfaceGetter, SubInterface.SubInterfaceSetter> {
    public interface SubInterfaceGetter extends SuperInterfaceGetter {}

    public interface SubInterfaceSetter extends SuperInterfaceSetter {}
}

These two classes compiles without a problem in eclipse jdt, but fails when compiling using javac or maven with the following error (using the complience level 1.5 in both environments):

test\subint\SubInterface.java:6: cannot find symbol
symbol  : class SuperInterfaceGetter
location: interface test.subint.SubInterface
    public interface SubInterfaceGetter extends SuperInterfaceGetter {}
                                                ^
test\subint\SubInterface.java:8: cannot find symbol
symbol  : class SuperInterfaceSetter
location: interface test.subint.SubInterface
    public interface SubInterfaceSetter extends SuperInterfaceSetter {}
                                                ^
test\subint\SubInterface.java:5: type parameter test.subint.SubInterface.SubInterfaceGetter is not within its bound
public interface SubInterface extends SuperInterface<SubInterface.SubInterfaceGetter, SubInterface.SubInterfaceSetter> {
                                                                 ^
test\subint\SubInterface.java:5: type parameter test.subint.SubInterface.SubInterfaceSetter is not within its bound
public interface SubInterface extends SuperInterface<SubInterface.SubInterfaceGetter, SubInterface.SubInterfaceSetter> {
                                                                                                  ^
4 errors

To make it compile outside of eclipse, I have to add two imports to the interface SubInterface.java:

import com.test.superint.SuperInterface.SuperInterfaceGetter;
import com.test.superint.SuperInterface.SuperInterfaceSetter;

But as soon as I do it, eclipse says these two imports are never used and remove them if the "Remove unused imports" is enabled

The only way to make the code compile in eclipse as well as javac/maven is by referring to the inner interfaces through the outer interface class:

package com.test.subint;

import com.test.superint.SuperInterface;

public interface SubInterface extends com.test.superint.SuperInterface<SubInterface.SubInterfaceGetter, SubInterface.SubInterfaceSetter> {
    public interface SubInterfaceGetter extends SuperInterface.SuperInterfaceGetter {}

    public interface SubInterfaceSetter extends SuperInterface.SuperInterfaceSetter {}
}

Additional information:
I'm using Java SDK 1.6.0_11