Camel netty component: Failed to create selector

Question

I am trying to use netty to consume bytes out of a tcp socket. I am using Apache Camel 2.12.1, Spring DSL and Windows. My route is pretty simple:

<camelContext xmlns="http://camel.apache.org/schema/spring" autoStartup="true">
    <route id="my-route">
        <from uri="netty:tcp://127.0.0.1:4102?sync=true&amp;textline=true" />
        <convertBodyTo type="java.lang.String" />
        <to uri="file:./data" />
    </route>
</camelContext>

I am getting this exception when starting the route:

2013-11-15 19:33:23,749 ERROR [Thread-5] - org.jboss.netty.channel.ChannelException: Failed to create a selector.
org.apache.camel.RuntimeCamelException: org.jboss.netty.channel.ChannelException: Failed to create a selector.
    at org.apache.camel.util.ObjectHelper.wrapRuntimeCamelException(ObjectHelper.java:1344) ~[camel-core-2.12.1.jar:2.12.1]
    at org.apache.camel.spring.SpringCamelContext.onApplicationEvent(SpringCamelContext.java:120) ~[camel-spring-2.12.1.jar:2.12.1]
    at org.apache.camel.spring.CamelContextFactoryBean.onApplicationEvent(CamelContextFactoryBean.java:301) ~[camel-spring-2.12.1.jar:2.12.1]
    ...
    at java.lang.Thread.run(Thread.java:724) [?:1.7.0_40]
Caused by: org.jboss.netty.channel.ChannelException: Failed to create a selector.
    at org.jboss.netty.channel.socket.nio.AbstractNioSelector.openSelector(AbstractNioSelector.java:337) ~[netty-3.7.0.Final.jar:?]
    at org.jboss.netty.channel.socket.nio.AbstractNioSelector.<init>(AbstractNioSelector.java:95) ~[netty-3.7.0.Final.jar:?]
    at org.jboss.netty.channel.socket.nio.NioServerBoss.<init>(NioServerBoss.java:49) ~[netty-3.7.0.Final.jar:?]
    at org.jboss.netty.channel.socket.nio.NioServerBossPool.newBoss(NioServerBossPool.java:55) ~[netty-3.7.0.Final.jar:?]
    at org.jboss.netty.channel.socket.nio.NioServerBossPool.newBoss(NioServerBossPool.java:26) ~[netty-3.7.0.Final.jar:?]
    at org.jboss.netty.channel.socket.nio.AbstractNioBossPool.init(AbstractNioBossPool.java:65) ~[netty-3.7.0.Final.jar:?]
    at org.jboss.netty.channel.socket.nio.NioServerBossPool.<init>(NioServerBossPool.java:40) ~[netty-3.7.0.Final.jar:?]
    at org.apache.camel.component.netty.NettyServerBossPoolBuilder.build(NettyServerBossPoolBuilder.java:65) ~[camel-netty-2.12.1.jar:2.12.1]
    at org.apache.camel.component.netty.SingleTCPNettyServerBootstrapFactory.startServerBootstrap(SingleTCPNettyServerBootstrapFactory.java:132) ~[camel-netty-2.12.1.jar:2.12.1]
    at org.apache.camel.component.netty.SingleTCPNettyServerBootstrapFactory.doStart(SingleTCPNettyServerBootstrapFactory.java:93) ~[camel-netty-2.12.1.jar:2.12.1]
    at org.apache.camel.support.ServiceSupport.start(ServiceSupport.java:61) ~[camel-core-2.12.1.jar:2.12.1]
    ... 100 more
Caused by: java.lang.NoSuchMethodError: org.jboss.netty.channel.socket.nio.SelectorUtil.open()Ljava/nio/channels/Selector;
    at org.jboss.netty.channel.socket.nio.AbstractNioSelector.openSelector(AbstractNioSelector.java:335) ~[netty-3.7.0.Final.jar:?]
    at org.jboss.netty.channel.socket.nio.AbstractNioSelector.<init>(AbstractNioSelector.java:95) ~[netty-3.7.0.Final.jar:?]
    at org.jboss.netty.channel.socket.nio.NioServerBoss.<init>(NioServerBoss.java:49) ~[netty-3.7.0.Final.jar:?]
    at org.jboss.netty.channel.socket.nio.NioServerBossPool.newBoss(NioServerBossPool.java:55) ~[netty-3.7.0.Final.jar:?]
    at org.jboss.netty.channel.socket.nio.NioServerBossPool.newBoss(NioServerBossPool.java:26) ~[netty-3.7.0.Final.jar:?]
    at org.jboss.netty.channel.socket.nio.AbstractNioBossPool.init(AbstractNioBossPool.java:65) ~[netty-3.7.0.Final.jar:?]
    at org.jboss.netty.channel.socket.nio.NioServerBossPool.<init>(NioServerBossPool.java:40) ~[netty-3.7.0.Final.jar:?]
    at org.apache.camel.component.netty.NettyServerBossPoolBuilder.build(NettyServerBossPoolBuilder.java:65) ~[camel-netty-2.12.1.jar:2.12.1]
    at org.apache.camel.component.netty.SingleTCPNettyServerBootstrapFactory.startServerBootstrap(SingleTCPNettyServerBootstrapFactory.java:132) ~[camel-netty-2.12.1.jar:2.12.1]
    at org.apache.camel.component.netty.SingleTCPNettyServerBootstrapFactory.doStart(SingleTCPNettyServerBootstrapFactory.java:93) ~[camel-netty-2.12.1.jar:2.12.1]
    ... 20 more

Any ideas with it is not starting? Thanks!

Answer 1

NoSuchMethodError is usually caused by having an incompatible jar (too old or too new) on the CLASSPATH.

(I have occassionally found the free JBoss Tattletale useful for identifying old duplicate copies of classes or jars hanging around on my CLASSPATH. However, duplication may not be the problem here.)