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From R J <rj201...@yahoo.com>
Subject Re: Cannot compaile a basic PutMerge.java program
Date Mon, 28 Jul 2014 05:51:54 GMT
Thanks a lot! I could compile with the added classpath:
$javac -cp $($HADOOP_HOME/bin/hadoop classpath) PutMerge.java
The above created PutMerge.class file.
Now I try to run:
$java PutMerge
Exception in thread "main" java.lang.NoClassDefFoundError: PutMerge
Caused by: java.lang.ClassNotFoundException: PutMerge
        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
Could not find the main class: PutMerge.  Program will exit.


I get the above error. 

I tried:
$set CLASSPATH=/usr/lib/hadoop/bin/hadoop
$java PutMerge

I still get the error. 




On Sunday, July 27, 2014 10:16 PM, Harsh J <harsh@cloudera.com> wrote:
 


The javac program can only find import dependencies referenced in a
program if it is also supplied on the javac classpath. Setting
HADOOP_HOME alone will not magically do this. Have you set an
appropriate classpath?

Try as below, perhaps:

javac -cp $($HADOOP_HOME/bin/hadoop classpath) PutMerge.java

Alternatively, consider using a modern build helper tool such as
Apache Maven for writing java applications, they make your work
easier.


On Mon, Jul 28, 2014 at 6:16 AM, R J <rj201244@yahoo.com> wrote:
> Hi All,
>
> I am new to programming on hadoop. I tried to compile the following program
> (example program from a hadoop book) on my linix server where I have Haddop
> installed:
> I get the errors:
> $javac PutMerge.java
> PutMerge.java:2: package org.apache.hadoop.conf does not exist
> import org.apache.hadoop.conf.Configuration;
>                              ^
> PutMerge.java:3: package org.apache.hadoop.fs does not exist
> import org.apache.hadoop.fs.FSDataInputStream;
>                            ^
> PutMerge.java:4: package org.apache.hadoop.fs does not exist
> import org.apache.hadoop.fs.FSDataOutputStream;
>                            ^
> PutMerge.java:5: package org.apache.hadoop.fs does not exist
> import org.apache.hadoop.fs.FileStatus;
>                            ^
> PutMerge.java:6: package org.apache.hadoop.fs does not exist
> import org.apache.hadoop.fs.FileSystem;
>                            ^
> PutMerge.java:7: package org.apache.hadoop.fs does not exist
> import org.apache.hadoop.fs.Path;
>
> I have $HADOOP_HOME set u:
> $echo $HADOOP_HOME
> /usr/lib/hadoop
>
> Could you please suggest how to compile this program? Thanks a lot.
>
> Shu
>
>
> ====PutMerge.java=========
> import java.io.IOException;
> import org.apache.hadoop.conf.Configuration;
> import org.apache.hadoop.fs.FSDataInputStream;
> import org.apache.hadoop.fs.FSDataOutputStream;
> import org.apache.hadoop.fs.FileStatus;
> import org.apache.hadoop.fs.FileSystem;
> import org.apache.hadoop.fs.Path;
> public class PutMerge {
>
> public static void main(String[] args) throws IOException {
> Configuration conf = new Configuration();
> FileSystem hdfs = FileSystem.get(conf);
> FileSystem local = FileSystem.getLocal(conf);
>
> Path inputDir = new Path(args[0]);
> Path hdfsFile = new Path(args[1]);
>
> try {
> FileStatus[] inputFiles = local.listStatus(inputDir);
> FSDataOutputStream out = hdfs.create(hdfsFile);
>
> for (int i=0; i<inputFiles.length; i++) {
> System.out.println(inputFiles[i].getPath().getName());
> FSDataInputStream in = local.open(inputFiles[i].getPath());
> byte buffer[] = new byte[256];
> int bytesRead = 0;
> while( (bytesRead = in.read(buffer)) > 0) {
> out.write(buffer, 0, bytesRead);
> }
> in.close();
> }
> out.close();
> } catch (IOException e) {
> e.printStackTrace();
> }
> }
> }
> =============
>



-- 
Harsh J
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