Exception in thread "ForkJoinPool-7-worker-1" java.lang.NullPointerException: Cannot invoke "com.google.common.util.concurrent.FluentFuture.get()" because the return value of "org.opendaylight.mdsal.binding.api.ReadTransaction.read(org.opendaylight.mdsal.common.api.LogicalDatastoreType, org.opendaylight.yangtools.binding.DataObjectIdentifier)" is null at org.opendaylight.openflowplugin.applications.bulk.o.matic.FlowReader.readFlowsX(FlowReader.java:91) at org.opendaylight.openflowplugin.applications.bulk.o.matic.FlowReader.run(FlowReader.java:70) at java.base/java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1423) at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:387) at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1312) at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1843) at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1808) at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:188) [MockitoHint] FlowReaderTest.testRun (see javadoc for MockitoHint): [MockitoHint] 1. Unused... -> at org.opendaylight.openflowplugin.applications.bulk.o.matic.FlowReaderTest.setUp(FlowReaderTest.java:46) [MockitoHint] ...args ok? -> at org.opendaylight.openflowplugin.applications.bulk.o.matic.FlowReader.readFlowsX(FlowReader.java:91)