Java Errors starting from ClassNotFoundException

Question

I have the following errors when i try to run my Netbeans aplication of a map reduce algorithm:

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/log4j/Level
at org.apache.hadoop.mapred.JobConf.<clinit>(JobConf.java:349)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:1121)
at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:88)
at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:72)
at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:125)
at org.apache.hadoop.security.Groups.<init>(Groups.java:54)
at org.apache.hadoop.security.Groups.getUserToGroupsMappingService(Groups.java:142)
at     
org.apache.hadoop.security.UserGroupInformation.initUGI(UserGroupInformation.java:243)
at 
org.apache.hadoop.security.UserGroupInformation.initialize(UserGroupInformation
.java:216)
at     
org.apache.hadoop.security.UserGroupInformation.ensureInitialized(UserGroupInformation
.java:207)
at   
org.apache.hadoop.security.UserGroupInformation.isSecurityEnabled(UserGroup
Information.java:286)
at org.apache.hadoop.security.UserGroupInformation.getLoginUser(UserGroup
Information.java:500)
at org.apache.hadoop.security.UserGroupInformation.getCurrentUser(UserGroup   
Information.java:483)
at org.apache.hadoop.mapreduce.Cluster.<init>(Cluster.java:73)
at org.apache.hadoop.mapreduce.Job.<init>(Job.java:133)
at org.apache.hadoop.mapreduce.Job.<init>(Job.java:138)
at cloudex.CloudEx.main(CloudEx.java:33)
Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Level
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
... 19 more

Could you please give me a hint on how to get rid of it? i do not know what it generates it

java.lang.ClassNotFoundException: org.apache.log4j.Level. The mentioned class (or, actually, the JAR file containing the mentioned class) is not found in the runtime class path. Makes sense, right? — BalusC
– BalusC, Commented Jan 18, 2013 at 15:31

smcg · Accepted Answer · 2013-01-18 15:31:58Z

2

You need to add the log4j jar to your classpath.

answered Jan 18, 2013 at 15:31

smcg

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David · Accepted Answer · 2013-01-18 15:36:11Z

1

Either add the log4j class to your classpath as @smcg has stated, or add the following into your project pom.xml if you're using maven.

<dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>1.2.17</version>
</dependency>

answered Jan 18, 2013 at 15:36

David

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Michael 'Maik' Ardan · Accepted Answer · 2013-01-18 15:36:56Z

0

Download Apache log4j *.jar file at log4j. Import external *.jar file to your project.

answered Jan 18, 2013 at 15:36

Michael 'Maik' Ardan

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