PDDL4J is an open source library under licence LGPL (http://www.gnu.org/licenses/).  The purpose of the PDDL4J is to facilitate the  java implementation of planners  based on the PDDL (Planning Description Language). The library contains a  parser on the last version of PDDL 3.0 and all the classes need to manipulate its  concepts. The parser can be configured to accept only specified requirements of  PDDL langage.