Re: NoClassDefFoundError when running Hadoop with HBase

[Fei Dong]

On Tue, Jan 24, 2012 at 5:01 PM, Stack <st...@duboce.net> wrote:

> On Tue, Jan 24, 2012 at 12:10 PM, Fei Dong <dongfei...@gmail.com> wrote:
> > I test the hbase shell on another machine, which can "put", "get"
> > record successfully. So I guess Zookeeper is running.
> >
>
> Whats difference between two machines?
>
> Oh, I launch one master and one slave on EC2 which have the same config.
I run a zkcli.sh on one slave machine and test hbase shell which shows it
can connect to HBASE master node and do put/get operations.


> > It is weird that it does not mention any path or class name behind
> > "NoClassDefFoundError"
> > It seems some error occurs when copying jar from JobTracker to
> > TaskTracker, or it does not copy.
> >
> > The task tracker error log:
> >
> > Exception in thread "main" java.lang.NoClassDefFoundError:
> > Caused by: java.lang.ClassNotFoundException:
>
>
> This says that you likely have mangled CLASSPATH:
>
> http://stackoverflow.com/questions/2159006/noclassdeffounderror-without-any-class-name
>
> Is that possible?
>
> Thanks. I comment

/*
String std_child_opts="-server "+
    "-XX:+HeapDumpOnOutOfMemoryError "+
    "-XX:+UseConcMarkSweepGC "+
    "-XX:+UseParNewGC ";
    //"-XX:ParallelGCThreads=8";

                conf.set("mapred.map.child.java.opts","-Xmx500m
"+std_child_opts);
                conf.set("mapred.reduce.child.java.opts","-Xmx1000m
"+std_child_opts);
conf.set("mapred.map.output.compression.codec","org.apache.hadoop.io.compress.SnappyCodec");

conf.set("mapred.output.compression.codec","org.apache.hadoop.io.compress.SnappyCodec");
*/
Then NoClassDefFoundError disappear, instead it shows the

"HBase is able to
connect to ZooKeeper but the connection closes immediately. This could
be a sign that the server has too many connections (30 is the
default)."

St.Ack
>
> >        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
> >        at java.security.AccessController.doPrivileged(Native Method)
> >        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
> >        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
> >        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
> >        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
> > Could not find the main class: .  Program will exit.
> >>
> >> St.Ack
> >
> >
> >
> > --
> > Best Regards,
> > --
> > Fei Dong
>



-- 
Best Regards,
-- 
Fei Dong
**