FULL PRODUCT VERSION :
java version " 1.7.0_07 "
Java(TM) SE Runtime Environment (build 1.7.0_07-b11)
Java HotSpot(TM) 64-Bit Server VM (build 23.3-b01, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
I have " public interface MyInterface<T extends Enum<T> & OtherInterface> " as the generic type of an interface, and one of the methods of the interface returns type T, which is obviously an enum. However, a separate static method that takes an enum as an argument will not recognize the returned type T as an enum.

See attached test case.

The attached test case fails to compile both in JDK 6 and JDK 7. It compiles fine in Eclipse 4.2.1.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
javac BugEnum.java

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The program should compile and produce the string " success " when run.
ACTUAL -
Java refuses to compile the class.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
  BugEnum.java:24: error: method getSerializationName in class BugEnum cannot be applied to given types;
                System.out.println(getSerializationName(testMessage.getCommand()));
                                   ^
  required: E
  found: INT#1
  reason: inferred type does not conform to declared bound(s)
    inferred: INT#1
    bound(s): Enum<INT#1>
  where E is a type-variable:
    E extends Enum<E> declared in method <E>getSerializationName(E)
  where CAP#1 is a fresh type-variable:
    CAP#1 extends INT#1 from capture of ?
  where INT#1 is an intersection type:
    INT#1 extends Enum<CAP#1>,Command
1 error

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
/**Illustration of Java Enum-related compile bug.
*@author Garret Wilson
*/
public class BugEnum {

public interface Command {}

public interface CommandMessage<C extends Enum<C> & Command> {
public C getCommand();
}

public enum TestCommand implements Command {SUCCESS, FAILURE}

public static class TestCommandMessage implements CommandMessage<TestCommand> {
@Override public TestCommand getCommand() {return TestCommand.SUCCESS;}
}

public static <E extends Enum<E>> String getSerializationName(final E e) {
return e.name().toString().toLowerCase();
}

public static void main(String... args) {
CommandMessage<?> testMessage=new TestCommandMessage();
System.out.println(getSerializationName(testMessage.getCommand()));
}

}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
This bug is hard to work around without removing the use of generics and/or having various (Object) casts and such.