Geoffrey De Smet created JBRULES-3406: ----------------------------------------- Summary: Planner: a Solution without a @PlanningEntityCollectionProperty or @PlanningEntityProperty should fail fast with a decent error message. Key: JBRULES-3406 URL: https://issues.jboss.org/browse/JBRULES-3406 Project: Drools Issue Type: Enhancement Security Level: Public (Everyone can see) Components: drools-planner Reporter: Geoffrey De Smet Assignee: Geoffrey De Smet Fix For: 5.4.0.CR1 " I accidently denoted the wrong class with the annotator @PlanningEntityCollectionProperty ; a class which was NOT a planning entity. Apparently, Drools Planner does not attempt to check for such a possibility, hence I get: {code} Exception in thread "main" java.lang.NullPointerException at org.drools.planner.core.domain.solution.SolutionDescriptor.getAllFacts(SolutionDescriptor.java:135) at org.drools.planner.core.solution.director.DefaultSolutionDirector.getWorkingFacts(DefaultSolutionDirector.java:129) at org.drools.planner.core.solution.director.DefaultSolutionDirector.resetWorkingMemory(DefaultSolutionDirector.java:123) at org.drools.planner.core.solution.director.DefaultSolutionDirector.setWorkingSolution(DefaultSolutionDirector.java:97) at org.drools.planner.core.solver.DefaultSolver.setPlanningProblem(DefaultSolver.java:97) at in.co.technovia.examduties.ExamDutiesApp.main(ExamDutiesApp.java:47) {code} Please check for such a possibility in future versions of Drools Planner and emit a more meaningful error message. " -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.jboss.org/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira