You must either use ReInit() or set the JavaCC option STATIC to false

I'm trying to test my project but when I try to do it parts I've have received this error:

Second call to constructor of static parser. You must either use ReInit() or set the JavaCC option STATIC to false during parser generation.

It happens because I need to execute a ReUnit command to update the reference to the new value.

I updated the code, just like it was suggested, with the command ReInit(), but now I have a error (NullPointerException). At this line, Imp1Parser.ReInit(stream), the error happens and stop the execution.

Could someone help me?