Hello.

I see the next issue during ODL tests: when multiple devices (~ 120 devices) are connecting to ODL controller on ODL start, the following issue is thrown:

2015-04-01 18:32:26,259 | WARN | entLoopGroup-6-2 | DefaultChannelPipeline | 116 - io.netty.common - 4.0.26.Final | An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.
java.lang.NullPointerException
at
org.opendaylight.openflowplugin.openflow.md.core.ConnectionConductorImpl.updatePort(ConnectionConductorImpl.java:298)[176:org.opendaylight.openflowplugin:0.1.1000.SNAPSHOT]
at
org.opendaylight.openflowplugin.openflow.md.core.ConnectionConductorImpl.processPortStatusMsg(ConnectionConductorImpl.java:283)[176:org.opendaylight.openflowplugin:0.1.1000.SNAPSHOT]
at
org.opendaylight.openflowplugin.openflow.md.core.ConnectionConductorImpl.onPortStatusMessage(ConnectionConductorImpl.java:275)[176:org.opendaylight.openflowplugin:0.1.1000.SNAPSHOT]
at
org.opendaylight.openflowjava.protocol.impl.core.connection.ConnectionAdapterImpl.consume(ConnectionAdapterImpl.java:303)[174:org.opendaylight.openflowjava.openflow-protocol-impl:0.6.0.SNAPSHOT]
at
org.opendaylight.openflowjava.protocol.impl.core.DelegatingInboundHandler.channelRead(DelegatingInboundHandler.java:46)[174:org.opendaylight.openflowjava.openflow-protocol-impl:0.6.0.SNAPSHOT]
at
io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:339)[115:io.netty.transport:4.0.26.Final]
at
io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:324)[115:io.netty.transport:4.0.26.Final]
at
io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)[141:io.netty.codec:4.0.26.Final]
at
io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:339)[115:io.netty.transport:4.0.26.Final]
at
io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:324)[115:io.netty.transport:4.0.26.Final]
at
io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:242)[141:io.netty.codec:4.0.26.Final]
at
io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:339)[115:io.netty.transport:4.0.26.Final]
at
io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:324)[115:io.netty.transport:4.0.26.Final]
at
io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:242)[141:io.netty.codec:4.0.26.Final]
at
io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:339)[115:io.netty.transport:4.0.26.Final]
at
io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:324)[115:io.netty.transport:4.0.26.Final]
at
io.netty.handler.timeout.ReadTimeoutHandler.channelRead(ReadTimeoutHandler.java:150)[142:io.netty.handler:4.0.26.Final]
at
org.opendaylight.openflowjava.protocol.impl.core.IdleHandler.channelRead(IdleHandler.java:39)[174:org.opendaylight.openflowjava.openflow-protocol-impl:0.6.0.SNAPSHOT]
at
io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:339)[115:io.netty.transport:4.0.26.Final]
at
io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:324)[115:io.netty.transport:4.0.26.Final]
at
io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:86)[115:io.netty.transport:4.0.26.Final]
at
io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:339)[115:io.netty.transport:4.0.26.Final]
at
io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:324)[115:io.netty.transport:4.0.26.Final]
at
io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:847)[115:io.netty.transport:4.0.26.Final]
at
io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:131)[115:io.netty.transport:4.0.26.Final]
at
io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:511)[115:io.netty.transport:4.0.26.Final]
at
io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:468)[115:io.netty.transport:4.0.26.Final]
at
io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:382)[115:io.netty.transport:4.0.26.Final]
at
io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:349)[115:io.netty.transport:4.0.26.Final]
at
io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:111)[116:io.netty.common:4.0.26.Final]
at
io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:137)[116:io.netty.common:4.0.26.Final]
at java.lang.Thread.run(Thread.java:724)[:1.7.0_25]

The issue is reproducible on Helium and Lithium OpenFlowPlugin versions and caused by racing conditions in ConnectionConductorImpl.
The sessionContext member is not set yet when onPortStatusMessage is called. As result, this.getSessionContext() in method ConnetionConductorImpl.updatePort() returns null:

297: } else