probleme with getExpectedTokensWithinCurrentRule in java

[Exemple Thales]

hello i try to find a sample for using getExpectedTokensWithinCurrentRule in antlr4

i have this source code

final ANTLRInputStream input = new ANTLRInputStream("AA + BB");

final CalcLexer lexer = new CalcLexer(input);

final CommonTokenStream tokens = new CommonTokenStream(lexer);

final CalcParser parser = new CalcParser(tokens);

final IntervalSet interval = parser.getExpectedTokensWithinCurrentRule();

but i have always an error : Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1

have you some sample for this