UniqueIdSchemeDelegator { public void removeDelegate(final String scheme) { ArgumentChecker.notNull(scheme, "scheme"); _schemeToDelegateMap.remove(scheme); } UniqueIdSchemeDelegator(final T defaultDelegate);  UniqueIdSchemeDelegator(final T defaultDelegate, final Map<String, T> schemePrefixToDelegateMap); T getDefaultDelegate(); Map<String, T> getDelegates(); Iterable<T> getAllDelegates(); T chooseDelegate(final String scheme); boolean registerDelegate(final String scheme, final T delegate); void removeDelegate(final String scheme);  }
@Test(expectedExceptions = IllegalArgumentException.class) public void test_removeDelegate_null() { UniqueIdSchemeDelegator<String> test = new UniqueIdSchemeDelegator<String>("default"); test.removeDelegate(null); }