hadoop-common-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Varun Thacker <varunthacker1...@gmail.com>
Subject Re: some doubts
Date Fri, 05 Mar 2010 19:14:13 GMT
This is how my jar looks like.
Its name is Election.jar

Inside the jar these are the files

Election.java
Election.class
Election$Reduce.class
Election$Map.class
META-INF/
Manifest-Version: 1.0

So what is the package information in this case.


On Fri, Mar 5, 2010 at 7:32 PM, Jones, Nick <nick.jones@amd.com> wrote:

> The path to the class needs to include the package information. (i.e.
> com.mycompany.mytool.election)
>
> Nick Jones
> Sent by radiation.
>
> On Mar 5, 2010, at 7:27 AM, "Varun Thacker"
> <varunthacker1989@gmail.com> wrote:
>
> > This is how my jar looks like.
> > Its name is Election.jar
> > Directory:hadoop@varun:~/hadoop-0.20.1
> > Inside the jar these are the files
> > Election.java
> > Election.class
> > Election$Reduce.class
> > Election$Map.class
> > META-INF/
> > Manifest-Version: 1.0
> > Created-By: 1.6.0_0 (Sun Microsystems Inc.)
> >
> > This is how i run it:
> > hadoop@varun:~/hadoop-0.20.1$ bin/hadoop jar Election.jar
> > Election.class
> > gutenberg gutenberg-output
> >
> > Exception in thread "main" java.lang.ClassNotFoundException:
> > Election.class
> >    at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
> >    at java.security.AccessController.doPrivileged(Native Method)
> >    at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
> >    at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
> >    at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
> >    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
> >    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)
> >
> > what am doing wrong?
> >
> >
> >
> > On Fri, Mar 5, 2010 at 10:40 AM, Eric Sammer <eric@lifeless.net>
> > wrote:
> >
> >> On 3/4/10 11:42 PM, Varun Thacker wrote:
> >>> I am using ubuntu Linux. I was able to get the standalone hadoop
> >>> cluster
> >>> running and run the wordcount example.
> >>> before i start writing hadoop programs i wanted to compile the
> >>> wordcount
> >>> example on my own.
> >>> So this is what i did to make the jar file on my own.
> >>>
> >>> javac -classpath /home/varun/hadoop/hadoop-0.
> >>> 20.1/hadoop-0.20.1-core.jar WordCount.java
> >>> jar -cvf wordcount.jar -C /media/d/iproggys/java/Hadoop/src/
> >>> wordcount/ .
> >>>
> >>> Is this the correct way to do it?
> >>
> >> That looks correct, yes. For anything more complicated than something
> >> like this, you'll want to use a build tool like Maven or Ant, though.
> >>
> >>> I had one more doubt while running the example.This is what i do
> >>> to run
> >> the
> >>> mapreduce job.
> >>> bin/hadoop jar hadoop-0.20.1-examples.jar wordcount gutenberg
> >>> gutenberg-output
> >>>
> >>> what is wordcount?
> >>> gutenberg being the input dir.
> >>> gutenberg-output being the out dir.
> >>
> >> The 'hadoop jar' command requires the jar file. The next argument is
> >> usually the name of the class to run from the jar file. This is not
> >> required if the jar's manifest file specifies it, though (which the
> >> examples jar does). In this case, this is just a normal argument
> >> passed
> >> to the main method of the main class. Like you said, the other
> >> arguments
> >> are the input and output directories.
> >>
> >> If you unjar the examples and look at the manifest file, you'll see
> >> the
> >> line:
> >> Main-Class: org/apache/hadoop/examples/ExampleDriver
> >>
> >> This is the class that gets run for this jar file.
> >>
> >> If you run 'hadoop jar' with no other arguments, you'll see the usage
> >> statement:
> >>
> >> # $HADOOP_HOME/bin/hadoop jar
> >> RunJar jarFile [mainClass] args...
> >>
> >> If you run the example jar without the arguments, you'll see the
> >> example
> >> code usage:
> >>
> >> # $HADOOP_HOME/bin/hadoop jar hadoop-0.20.1+152-examples.jar
> >> An example program must be given as the first argument.
> >> Valid program names are:
> >> aggregatewordcount: An Aggregate based map/reduce program that counts
> >> the words in the input files.
> >> aggregatewordhist: An Aggregate based map/reduce program that
> >> computes
> >> the histogram of the words in the input files.
> >> dbcount: An example job that count the pageview counts from a
> >> database.
> >> grep: A map/reduce program that counts the matches of a regex in the
> >> input.
> >> join: A job that effects a join over sorted, equally partitioned
> >> datasets
> >> multifilewc: A job that counts words from several files.
> >> pentomino: A map/reduce tile laying program to find solutions to
> >> pentomino problems.
> >> pi: A map/reduce program that estimates Pi using monte-carlo method.
> >> randomtextwriter: A map/reduce program that writes 10GB of random
> >> textual data per node.
> >> randomwriter: A map/reduce program that writes 10GB of random data
> >> per
> >> node.
> >> secondarysort: An example defining a secondary sort to the reduce.
> >> sleep: A job that sleeps at each map and reduce task.
> >> sort: A map/reduce program that sorts the data written by the random
> >> writer.
> >> sudoku: A sudoku solver.
> >> teragen: Generate data for the terasort
> >> terasort: Run the terasort
> >> teravalidate: Checking results of terasort
> >> wordcount: A map/reduce program that counts the words in the input
> >> files.
> >>
> >> Note that 'wordcount' is one of the options.
> >>
> >> Hope this helps.
> >> --
> >> Eric Sammer
> >> eric@lifeless.net
> >> http://esammer.blogspot.com
> >>
> >
> >
> >
> > --
> >
> >
> > Regards,
> > Varun Thacker
> > http://varunthacker.wordpress.com
>
>


-- 


Regards,
Varun Thacker
http://varunthacker.wordpress.com

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message