NullPointerException at TopologyProvider.onSessionInitiated() when snmp4sdn plugin startup

2017-01-04 13:28:35,492 | WARN | l for user karaf | snmp4sdn | 281 - org.opendaylight.snmp4sdn - 0.4.2.Boron-SR2 | Invocation of 'setBroker' failed. java.lang.NullPointerException at org.opendaylight.snmp4sdn.internal.TopologyProvider.onSessionInitiated(TopologyProvider.java:80) at org.opendaylight.controller.md.sal.binding.util.BindingContextUtils.createProviderContextAndInitialize(BindingContextUtils.java:56) at org.opendaylight.controller.sal.binding.impl.RootBindingAwareBroker.registerProvider(RootBindingAwareBroker.java:187) at org.opendaylight.controller.sal.binding.impl.RootBindingAwareBroker.registerProvider(RootBindingAwareBroker.java:175) at org.opendaylight.snmp4sdn.internal.TopologyProvider.registerProvider(TopologyProvider.java:126) at org.opendaylight.snmp4sdn.internal.TopologyProvider.setBroker(TopologyProvider.java:110) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)[:1.8.0_91] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)[:1.8.0_91] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)[:1.8.0_91] at java.lang.reflect.Method.invoke(Method.java:498)[:1.8.0_91]
at org.apache.felix.dm.InvocationUtil.invokeMethod(InvocationUtil.java:111) at org.apache.felix.dm.InvocationUtil.invokeCallbackMethod(InvocationUtil.java:66) at org.apache.felix.dm.impl.ComponentImpl.invokeCallbackMethod(ComponentImpl.java:688) at org.apache.felix.dm.impl.dependencies.ServiceDependencyImpl.invoke(ServiceDependencyImpl.java:704) at org.apache.felix.dm.impl.dependencies.ServiceDependencyImpl.invokeAdded(ServiceDependencyImpl.java:544) at org.apache.felix.dm.impl.dependencies.ServiceDependencyImpl.invokeAdded(ServiceDependencyImpl.java:1074) at org.apache.felix.dm.impl.ComponentImpl.configureServices(ComponentImpl.java:1010) at org.apache.felix.dm.impl.ComponentImpl.configureService(ComponentImpl.java:839) at org.apache.felix.dm.impl.ComponentImpl.activateService(ComponentImpl.java:603) at org.apache.felix.dm.impl.ComponentImpl.access$000(ComponentImpl.java:52) at org.apache.felix.dm.impl.ComponentImpl$3.run(ComponentImpl.java:156) at org.apache.felix.dm.impl.SerialExecutor$1.run(SerialExecutor.java:47) at org.apache.felix.dm.impl.SerialExecutor.scheduleNext(SerialExecutor.java:84) at org.apache.felix.dm.impl.SerialExecutor.access$000(SerialExecutor.java:33) at org.apache.felix.dm.impl.SerialExecutor$1.run(SerialExecutor.java:50) at org.apache.felix.dm.impl.SerialExecutor.scheduleNext(SerialExecutor.java:84) at org.apache.felix.dm.impl.SerialExecutor.execute(SerialExecutor.java:68) at org.apache.felix.dm.impl.ComponentImpl.calculateStateChanges(ComponentImpl.java:231) at org.apache.felix.dm.impl.ComponentImpl.start(ComponentImpl.java:399) at org.apache.felix.dm.DependencyManager.add(DependencyManager.java:169) at org.opendaylight.controller.sal.core.ComponentActivatorAbstractBase.start(ComponentActivatorAbstractBase.java:346) at org.opendaylight.snmp4sdn.internal.Activator.start(Activator.java:140) at org.eclipse.osgi.framework.internal.core.BundleContextImpl$1.run(BundleContextImpl.java:711) at java.security.AccessController.doPrivileged(Native Method)[:1.8.0_91] at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:702) at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:683) at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:381) at org.eclipse.osgi.framework.internal.core.AbstractBundle.updateWorker(AbstractBundle.java:645) at org.eclipse.osgi.framework.internal.core.AbstractBundle.update(AbstractBundle.java:592) at org.eclipse.osgi.framework.internal.core.AbstractBundle.update(AbstractBundle.java:575) at org.apache.karaf.bundle.command.Update.doExecute(Update.java:43)
at org.apache.karaf.bundle.command.BundleCommand.doExecute(BundleCommand.java:49) at org.apache.karaf.bundle.command.BundleCommandWithConfirmation.doExecute(BundleCommandWithConfirmation.java:34) at org.apache.karaf.shell.console.AbstractAction.execute(AbstractAction.java:33)[27:org.apache.karaf.shell.console:3.0.7] at org.apache.karaf.shell.console.OsgiCommandSupport.execute(OsgiCommandSupport.java:39)[27:org.apache.karaf.shell.console:3.0.7] at org.apache.karaf.shell.commands.basic.AbstractCommand.execute(AbstractCommand.java:33)[27:org.apache.karaf.shell.console:3.0.7] at Proxy46025784_062c_48e9_850e_2cd2112be581.execute(Unknown Source)[:] at Proxy46025784_062c_48e9_850e_2cd2112be581.execute(Unknown Source)[:] at org.apache.felix.gogo.runtime.CommandProxy.execute(CommandProxy.java:78)[27:org.apache.karaf.shell.console:3.0.7] at org.apache.felix.gogo.runtime.Closure.executeCmd(Closure.java:480)[27:org.apache.karaf.shell.console:3.0.7] at org.apache.felix.gogo.runtime.Closure.executeStatement(Closure.java:406)[27:org.apache.karaf.shell.console:3.0.7] at org.apache.felix.gogo.runtime.Pipe.run(Pipe.java:108)[27:org.apache.karaf.shell.console:3.0.7] at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:182)[27:org.apache.karaf.shell.console:3.0.7] at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:119)[27:org.apache.karaf.shell.console:3.0.7] at org.apache.felix.gogo.runtime.CommandSessionImpl.execute(CommandSessionImpl.java:94) at org.apache.karaf.shell.console.impl.jline.ConsoleImpl.run(ConsoleImpl.java:210) at org.apache.karaf.shell.console.impl.jline.LocalConsoleManager$2$1$1.run(LocalConsoleManager.java:109) at java.security.AccessController.doPrivileged(Native Method)[:1.8.0_91] at org.apache.karaf.jaas.modules.JaasHelper.doAs(JaasHelper.java:57)[28:org.apache.karaf.jaas.modules:3.0.7] at org.apache.karaf.shell.console.impl.jline.LocalConsoleManager$2$1.run(LocalConsoleManager.java:102)[27:org.apache.karaf.shell.console:3.0.7]