protected void reportAmbiguity(DFA dfa,
								   DFAState D, // the DFA state from execATN() that had SLL conflicts
								   int startIndex, int stopIndex,
								   boolean exact,
								   BitSet ambigAlts,
								   ATNConfigSet configs) // configs that LL not SLL considered conflicting
	{
		if ( debug || retry_debug ) {
			Interval interval = Interval.of(startIndex, stopIndex);
			System.out.println("reportAmbiguity "+
							   ambigAlts+":"+configs+
                               ", input="+parser.getTokenStream().getText(interval));
        }
        if ( parser!=null ) parser.getErrorListenerDispatch().reportAmbiguity(parser, dfa, startIndex, stopIndex,
																			  exact, ambigAlts, configs);
    }
If context sensitive parsing, we know it's ambiguity not conflict
runtime/Java/src/org/antlr/v4/runtime/atn/ParserATNSimulator.java