It seems when running any example problem with any key requirement other than :strips JavaGP will throw the error:
MacBook-Pro-di-Giuseppe:javagp-bin-1-2 Beppe$ java -jar javagp.jar -d examples/pddl/blocksworld/blocksworld.pddl -p examples/pddl/blocksworld/pb1.pddl
GRAVE: Parser error at line 2, column 24 file (blocksworld.pddl) : Require key ":equality" forbidden due to parser requirement options.
pddl4j.ParserException: Parse error in PDDL Domain
at graphplan.parser.PDDLPlannerAdapter.<init>(PDDLPlannerAdapter.java:106)
at graphplan.Graphplan.main(Graphplan.java:195)</init>
JavaGP will successfully find a plan in the case of Blocksworld without :equality. The same error applies to any other key, listing "Require key ":name-of-key" forbidden due to parser requirement options." for each key.
Best Regards
This is not necessarily a bug, since it is stopping the parser when you state that you need something the parser cannot do. The erro might have been in the PDDL, but before I close this bug, I want to make sure you agree with my interpretation.
I will try to work this problem tonight.