public Collection<JID> getAdmins() {
        return administrators;
    }
@Test
    public void testRemoveFullJid() throws Exception
    {
        // Setup test fixture.
        final String groupName = "unit-test-group-k";
        final Group group = groupManager.createGroup(groupName);
        final JID fullJid = new JID("unit-test-user-k", "example.org", "unit-test-resource-k");
        final JID bareJid = fullJid.asBareJID();
        group.getAdmins().add(bareJid);

        // Execute system under test.
        final boolean result = group.getAdmins().remove(fullJid);

        // Verify results.
        assertTrue(result);
        assertFalse(group.getAdmins().contains(fullJid));
        assertFalse(group.getAdmins().contains(bareJid));
    }