DiskUserDataStore implements UserDataStore { @Override public void getUsersEntityList(UserListCallback userListCallback) { throw new UnsupportedOperationException("Operation is not available!!!"); }  @Override void getUsersEntityList(UserListCallback userListCallback); @Override void getUserEntityDetails(int id,
                                     final UserDetailsCallback userDetailsCallback);  }
@Test public void testGetUserEntityListUnsupported() { expectedException.expect(UnsupportedOperationException.class); diskUserDataStore.getUsersEntityList(null); }