public String getErrorHeader(RecognitionException e) {
		int line = e.getOffendingToken().getLine();
		int charPositionInLine = e.getOffendingToken().getCharPositionInLine();
		return "line "+line+":"+charPositionInLine;
	}
What is the error header, normally line/character position information?
runtime/Java/src/org/antlr/v4/runtime/Recognizer.java