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I have implemented a pagerank algorithm using Java/NetBeans and I have build the .jar file to execute it in hadoop.

While trying to execute it i came up with this error:

Exception in thread "main" java.lang.UnsupportedClassVersionError: Pagerank : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:295)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:247)
at org.apache.hadoop.util.RunJar.main(RunJar.java:149)

With a little search I found that there might be Java version compatibility problem. Now i use the hadoop 1.04 version with Java 1.6. I changed my NetBeans project to use the same version.

Regarding some .jar libraries I included in my project all of them are taken from my hadoop installation archives except from one (hadoop-core) which I had to download manually from MavenRepository (http://mvnrepository.com/artifact/org.apache.hadoop/hadoop-core). I downloaded the 1.0.4 version which is the Hadoop version I use.

With all that said, things seem pretty compatible to me, but then again I'm new in using Hadoop and I hope I can get some insight on the issue.

user2052763
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1 Answers1

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Why don't you compile your source files in the host itself and package them into a Jar. Yoou can run the following commands:

  1. Copy all your Java files to a directory.
  2. mkdir classes
  3. javac -classpath <path_to_hadoop_library_jars_separated_by_colon_if_more_than_one> -d classes *.java
  4. jar -cvf myjar.jar -C classes/ .

Now try to run this JAR. Let's see if it works.

aa8y
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