"nioEventLoopGroup-11-3" prio=10 tid=0x00007f9b6c510000 nid=0x131b waiting for monitor entry [0x00007f9ac9a94000]
java.lang.Thread.State: BLOCKED (on object monitor)
at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:231)

• waiting to lock <0x00000000b20126e8> (a org.apache.log4j.ConsoleAppender)
  at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:66)
  at org.apache.log4j.Category.callAppenders(Category.java:193)
  at org.apache.log4j.Category.forcedLog(Category.java:365)
  at org.apache.log4j.Category.log(Category.java:772)
  at org.ops4j.pax.logging.service.internal.PaxLoggerImpl.inform(PaxLoggerImpl.java:143)
  at org.ops4j.pax.logging.internal.TrackingLogger.inform(TrackingLogger.java:86)
  at org.ops4j.pax.logging.slf4j.Slf4jLogger.info(Slf4jLogger.java:476)
  at org.opendaylight.openflowjava.protocol.impl.core.TcpChannelInitializer.initChannel(TcpChannelInitializer.java:60)
  at org.opendaylight.openflowjava.protocol.impl.core.TcpChannelInitializer.initChannel(TcpChannelInitializer.java:32)

"DEFAULT_POOL_9" prio=10 tid=0x00007f9b381a8000 nid=0x6a40 waiting for monitor entry [0x00007f9ac9e99000]
java.lang.Thread.State: BLOCKED (on object monitor)
at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:231)

• waiting to lock <0x00000000b20126e8> (a org.apache.log4j.ConsoleAppender)
  at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:66)
  at org.apache.log4j.Category.callAppenders(Category.java:193)
  at org.apache.log4j.Category.forcedLog(Category.java:365)
  at org.apache.log4j.Category.log(Category.java:772)
  at org.ops4j.pax.logging.service.internal.PaxLoggerImpl.warn(PaxLoggerImpl.java:151)
  at org.ops4j.pax.logging.internal.TrackingLogger.warn(TrackingLogger.java:91)
  at org.ops4j.pax.logging.slf4j.Slf4jLogger.warn(Slf4jLogger.java:697)
  at com.cxtrm.contexcontrol.underlaymanager.impl.controllermanager.ControllerStatusSentry$2.work(ControllerStatusSentry.java:107)
  java.lang.Thread.State: BLOCKED (on object monitor)
  at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:231)
• waiting to lock <0x00000000b20126e8> (a org.apache.log4j.ConsoleAppender)
  at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:66)
  at org.apache.log4j.Category.callAppenders(Category.java:193)
  at org.apache.log4j.Category.forcedLog(Category.java:365)
  at org.apache.log4j.Category.log(Category.java:772)
  at org.ops4j.pax.logging.service.internal.PaxLoggerImpl.warn(PaxLoggerImpl.java:151)
  at org.ops4j.pax.logging.internal.TrackingLogger.warn(TrackingLogger.java:91)
  at org.ops4j.pax.logging.slf4j.Slf4jLogger.warn(Slf4jLogger.java:716)
  at org.opendaylight.openflowplugin.openflow.md.core.ErrorHandlerSimpleImpl.handleException(ErrorHandlerSimpleImpl.java:35)
  at org.opendaylight.openflowplugin.openflow.md.core.HandshakeManagerImpl.shake(HandshakeManagerImpl.java:117)
  at org.opendaylight.openflowplugin.openflow.md.core.HandshakeStepWrapper.run(HandshakeStepWrapper.java:47)
  at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)

Should consider working with log4j version 2 and higher. It can be possible by working with log4j-slf4j-impl instead of log4j-over-slf4j.