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From Harsh J <ha...@cloudera.com>
Subject Re: cannot start tasktracker because java.lang.NullPointerException
Date Mon, 01 Sep 2014 15:15:19 GMT
It appears you have made changes to the source and recompiled it. The
actual release source line 247 of the failing class can be seen at
https://github.com/apache/hadoop-common/blob/release-1.2.1/src/mapred/org/apache/hadoop/mapred/TaskTracker.java#L247,
which can never end in a NPE.

You need to figure out your own custom code changes on that line in your
local sources to determine your problem.
On Sep 1, 2014 8:42 PM, "Dereje Teklu" <dereteklu@gmail.com> wrote:

> I created Single node cluster using Hadoop 1.2.1 following Running Hadoop
> on Ubuntu Linux(single node cluster)
> <http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-single-node-cluster/>.However
> while trying to run single node cluster I found error cannot start
> tasktracker because java.lang.NullPointerException at.....which is shown on
> log file.
>
> Tasktracker log file:
>
> 2014-08-26 23:20:07,380 INFO org.apache.hadoop.mapred.TaskTracker: STARTUP_MSG: /************************************************************
> STARTUP_MSG: Starting TaskTracker
> STARTUP_MSG:   host = ubuntu/127.0.1.1
> STARTUP_MSG:   args = []
> STARTUP_MSG:   version = 1.2.2-SNAPSHOT
> STARTUP_MSG:   build =  -r ; compiled by 'dere' on Tue Aug 12 03:45:50 PDT 2014
> STARTUP_MSG:   java = 1.7.0_65
> ************************************************************/2014-08-26 23:20:07,773
INFO org.apache.hadoop.metrics2.impl.MetricsConfig: loaded properties from hadoop-metrics2.properties2014-08-26
23:20:07,861 INFO org.apache.hadoop.metrics2.impl.MetricsSourceAdapter: MBean for source MetricsSystem,sub=Stats
registered.2014-08-26 23:20:07,862 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl:
Scheduled snapshot period at 10 second(s).2014-08-26 23:20:07,862 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl:
TaskTracker metrics system started2014-08-26 23:20:07,876 ERROR org.apache.hadoop.mapred.TaskTracker:
Can not start task tracker because java.lang.NullPointerException
>     at org.apache.hadoop.mapred.TaskTracker.<init>(TaskTracker.java:247)
>     at org.apache.hadoop.mapred.TaskTracker.main(TaskTracker.java:3965)
> 2014-08-26 23:20:07,876 INFO org.apache.hadoop.mapred.TaskTracker: SHUTDOWN_MSG: /************************************************************
> SHUTDOWN_MSG: Shutting down TaskTracker at ubuntu/127.0.1.1
> ************************************************************/
>
> core-site.xml
> <?xml version="1.0"?> <?xml-stylesheet type="text/xsl" href=
> "configuration.xsl"?> <!-- Put site-specific property overrides in this
> file. --> <configuration> <property> <name>hadoop.tmp.dir</name>
<value>/
> app/hadoop/tmp</value> <description>A base for other temporary directories
> .</description> </property> <property> <name>fs.default.name</name>
<value
> >hdfs://localhost:54310</value> <description>The name of the default file
> system. A URI whose scheme and authority determine the FileSystem
> implementation. The uri's scheme determines the config property (fs.SCHEME
> .impl) naming the FileSystem implementation class. The uri's authority is
> used to determine the host, port, etc. for a filesystem.</description> </
> property> </configuration>
>
> hdfs-site.xml
> <?xml version="1.0"?> <?xml-stylesheet type="text/xsl" href=
> "configuration.xsl"?> <!-- Put site-specific property overrides in this
> file. --> <configuration> <property> <name>dfs.replication</name>
<value>1
> </value> <description>Default block replication. The actual number of
> replications can be specified when the file is created. The default is
> used if replication is not specified in create time. </description> </
> property> </configuration>
>
> mapred-site.xml
> <?xml version="1.0"?> <?xml-stylesheet type="text/xsl" href=
> "configuration.xsl"?> <!-- Put site-specific property overrides in this
> file. --> <configuration> <property> <name>mapred.job.tracker</name>
<
> value>localhost:54311</value> <description>The host and port that the
> MapReduce job tracker runs at. If "local", then jobs are run in-process
> as a single map and reduce task. </description> </property> </
> configuration>
>
> jps output
> dere@ubuntu:~/Desktop/hadoop-1.2.1/bin$ jps
> 3165 JobTracker
> 3370 Jps
> 3086 SecondaryNameNode
> 2766 NameNode
> 2911 DataNode
>
> What would be the solution for this problem? Please help me in finding the solution for
this problem.
>
> I tried all possible methods to solve this, but not successful. Any pointers will help
me.
>
>
>

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