Substitution { protected abstract String group(int index, int groupNumber); Substitution();  Substitution(String replacementPrefixes); final String substitute(String input); final void substitute(StringBuilder buf, String input);  }
@Test public void emptyResult() { assertEquals(0, MatchResultSubstitution.EMPTY_MATCH_RESULT.groupCount()); assertEquals("", MatchResultSubstitution.EMPTY_MATCH_RESULT.group(0)); }