private static enum Test{
    TEST1, TEST2;
}

private class<T> TestClass{

    Map<T, String> map = new HashMap<T, String>();

    public void add(T obj, String name){
        map.put(obj, name);
    }

    public String get(T obj){
        return map.get(obj);
    }

}

// Somewhere... such as a unit test

TestClass<Test> test = new TestClass<Test>();
assertNull(test.get(Test.TEST1));
test.add(Test.TEST1, "somename");
assertNotNull(test.get(Test.TEST1)); // FAILS TO ASSERT