Exception in thread "main" java.util.concurrent.CompletionException: java.lang.NullPointerException
	at java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:273)
	at java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:280)
	at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1592)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
	at org.drools.core.conflict.PhreakConflictResolver.doCompare(PhreakConflictResolver.java:54)
	at org.drools.core.conflict.PhreakConflictResolver.compare(PhreakConflictResolver.java:45)
	at org.drools.core.conflict.PhreakConflictResolver.compare(PhreakConflictResolver.java:27)
	at org.drools.core.util.BinaryHeapQueue.compare(BinaryHeapQueue.java:301)
	at org.drools.core.util.BinaryHeapQueue.percolateDownMaxHeap(BinaryHeapQueue.java:239)
	at org.drools.core.util.BinaryHeapQueue.dequeue(BinaryHeapQueue.java:213)
	at org.drools.core.util.BinaryHeapQueue.dequeue(BinaryHeapQueue.java:185)
	at org.drools.core.common.AgendaGroupQueueImpl.remove(AgendaGroupQueueImpl.java:249)
	at org.drools.core.common.AgendaItemImpl.dequeue(AgendaItemImpl.java:328)
	at org.drools.core.common.AgendaItemImpl.remove(AgendaItemImpl.java:340)
	at org.drools.core.phreak.RuleExecutor.removeRuleAgendaItemWhenEmpty(RuleExecutor.java:197)
	at org.drools.core.phreak.RuleExecutor.fire(RuleExecutor.java:167)
	at org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:89)
	at org.drools.core.concurrent.AbstractRuleEvaluator.internalEvaluateAndFire(AbstractRuleEvaluator.java:37)
	at org.drools.core.concurrent.SequentialRuleEvaluator.evaluateAndFire(SequentialRuleEvaluator.java:43)
	at org.drools.core.common.DefaultAgenda.fireLoop(DefaultAgenda.java:1074)
	at org.drools.core.common.DefaultAgenda.internalFireAllRules(DefaultAgenda.java:1021)
	at org.drools.core.common.CompositeDefaultAgenda.lambda$parallelFire$1(CompositeDefaultAgenda.java:148)
	at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
	... 3 more