I have Windows 7, Java 8, Maven and Eclipse. I've created a Maven project and used almost exactly the same code as here.
It's just a simple "word count" sample. I try to launch the "driver" program from Eclipse, I provide command line arguments (the input file and the output directory) and get the following error:
Exception in thread "main" java.lang.NullPointerException at
java.lang.ProcessBuilder.start(ProcessBuilder.java:1012) at
org.apache.hadoop.util.Shell.runCommand(Shell.java:404) at
org.apache.hadoop.util.Shell.run(Shell.java:379) at
org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:589) at
org.apache.hadoop.util.Shell.execCommand(Shell.java:678) at
org.apache.hadoop.util.Shell.execCommand(Shell.java:661) at
org.apache.hadoop.fs.RawLocalFileSystem.setPermission(RawLocalFileSystem.java:639) at
org.apache.hadoop.fs.RawLocalFileSystem.mkdirs(RawLocalFileSystem.java:435) at
org.apache.hadoop.fs.FilterFileSystem.mkdirs(FilterFileSystem.java:277) at
org.apache.hadoop.mapreduce.JobSubmissionFiles.getStagingDir(JobSubmissionFiles.java:125) at
org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:344) at
org.apache.hadoop.mapreduce.Job$10.run(Job.java:1268) at
org.apache.hadoop.mapreduce.Job$10.run(Job.java:1265) at
java.security.AccessController.doPrivileged(Native Method) at
javax.security.auth.Subject.doAs(Subject.java:422) at
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491) at
org.apache.hadoop.mapreduce.Job.submit(Job.java:1265) at
org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:1286) at
misc.projects.hadoop.exercises.WordCountDriverApp.main(WordCountDriverApp.java:29)
The failing line (WordCountDriverApp.java:29) contains the command to launch the job:
job.waitForCompletion(true)
I want to make it work and therefore I want to understand something:
Do I have to provide any hdfs-site.xml, yarn-site.xml, ... all this, if I want just the local mode (without any cluster)? I don't have these XML config files now. As far as I remember, the defaults are all OK for the local mode, maybe I am wrong.
Is it possible at all under Windows (to launch any Hadoop jobs whatsoever) or the whole Hadoop thing is Linux-only?
P.S.: The Hadoop dependency is the following:
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-client</artifactId>
<version>2.2.0</version>
<scope>provided</scope>
</dependency>
