openjpa NPE

testSeparateChild(org.apache.openjpa.persistence.relations.TestParallelEagerMap)  Time elapsed: 0.076 sec  <<< ERROR!
<openjpa-2.4.2-r422266:1777108 fatal general error> org.apache.openjpa.persistence.PersistenceException: null
	at org.apache.openjpa.kernel.BrokerImpl.flush(BrokerImpl.java:1883)
	at org.apache.openjpa.kernel.DelegatingBroker.flush(DelegatingBroker.java:1044)
	at org.apache.openjpa.persistence.EntityManagerImpl.flush(EntityManagerImpl.java:664)
	at org.apache.openjpa.persistence.relations.TestParallelEagerMap.testSeparateChild(TestParallelEagerMap.java:81)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at junit.framework.TestCase.runTest(TestCase.java:176)
	at org.apache.openjpa.persistence.test.AbstractPersistenceTestCase.runTest(AbstractPersistenceTestCase.java:578)
	at junit.framework.TestCase.runBare(TestCase.java:141)
	at org.apache.openjpa.persistence.test.AbstractPersistenceTestCase.runBare(AbstractPersistenceTestCase.java:565)
	at org.apache.openjpa.persistence.test.AbstractPersistenceTestCase.runBare(AbstractPersistenceTestCase.java:541)
	at junit.framework.TestResult$1.protect(TestResult.java:122)
	at junit.framework.TestResult.runProtected(TestResult.java:142)
	at junit.framework.TestResult.run(TestResult.java:125)
	at junit.framework.TestCase.run(TestCase.java:129)
	at org.apache.openjpa.persistence.test.AbstractPersistenceTestCase.run(AbstractPersistenceTestCase.java:206)
	at junit.framework.TestSuite.runTest(TestSuite.java:252)
	at junit.framework.TestSuite.run(TestSuite.java:247)
	at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:86)
	at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:367)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeWithRerun(JUnit4Provider.java:274)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:238)
	at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:161)
	at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:290)
	at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:242)
	at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:121)
Caused by: java.lang.NullPointerException
	at org.apache.openjpa.jdbc.meta.strats.RelationFieldStrategy.getMapKeyObj(RelationFieldStrategy.java:353)
	at org.apache.openjpa.jdbc.meta.strats.RelationFieldStrategy.setMapKey(RelationFieldStrategy.java:311)
	at org.apache.openjpa.jdbc.meta.strats.RelationFieldStrategy.insert(RelationFieldStrategy.java:294)
	at org.apache.openjpa.jdbc.meta.FieldMapping.insert(FieldMapping.java:625)
	at org.apache.openjpa.jdbc.kernel.AbstractUpdateManager.insert(AbstractUpdateManager.java:238)
	at org.apache.openjpa.jdbc.kernel.AbstractUpdateManager.populateRowManager(AbstractUpdateManager.java:165)
	at org.apache.openjpa.jdbc.kernel.AbstractUpdateManager.flush(AbstractUpdateManager.java:96)
	at org.apache.openjpa.jdbc.kernel.AbstractUpdateManager.flush(AbstractUpdateManager.java:77)
	at org.apache.openjpa.jdbc.kernel.JDBCStoreManager.flush(JDBCStoreManager.java:731)
	at org.apache.openjpa.kernel.DelegatingStoreManager.flush(DelegatingStoreManager.java:131)
	at org.apache.openjpa.kernel.BrokerImpl.flush(BrokerImpl.java:2206)
	at org.apache.openjpa.kernel.BrokerImpl.flushSafe(BrokerImpl.java:2103)
	at org.apache.openjpa.kernel.BrokerImpl.flush(BrokerImpl.java:1874)
	... 27 more