On java program running on ubuntu

[sasimca007]

Hello friends,
I installed java with the following command:
sudo apt-get update
synaptic
In synaptic i searched for sun-java6-jdk and marked and applied.

After that i wrote a program and complied with javac /java/Hello.java it showed no errors and i run the program with java /java/Hello.java and it shows the follwing errors

Exception in thread "main" java.lang.NoClassDefFoundError: java/Hello.java
at gnu.java.lang.MainThread.run(libgcj.so.7)
Caused by: java.lang.ClassNotFoundException: java/Hello.java
at java.lang.Class.forName(libgcj.so.7)
at gnu.java.lang.MainThread.run(libgcj.so.7)

I think it is for not setting classpath and anybody helps me for setting classpath How to set classpath? and where to set classpath? in ubuntu

[JosAH]

Don't try to run the source file Hello.java, simply run the Hello class file. (no .class
extension used, the VM figures it out).
You do have to compile your source file Hello.java though.

kind regards,

Jos

[sasimca007]

Hello friend,
After running class file also i am getting the following error:

Exception in thread "main" java.lang.NoClassDefFoundError: Hello.class
at gnu.java.lang.MainThread.run(libgcj.so.7)
Caused by: java.lang.ClassNotFoundException: Hello.class not found in gnu.gcj.runtime.SystemClassLoader{urls=[file:./], parent=gnu.gcj.runtime.ExtensionClassLoader{urls=[], parent=null}}
at java.net.URLClassLoader.findClass(libgcj.so.7)
at java.lang.ClassLoader.loadClass(libgcj.so.7)
at java.lang.ClassLoader.loadClass(libgcj.so.7)
at java.lang.Class.forName(libgcj.so.7)
at gnu.java.lang.MainThread.run(libgcj.so.7)

[JosAH]

Go to the directrory where your compiled Hello.class file is stored. Type this:

java -cp . Hello
 

This tells the VM (java) to look for classes in the current directory (the dot).

kind regards,

Jos

[satch]

Go to the directrory where your compiled Hello.class file is stored. Type this:

java -cp . Hello
 

This tells the VM (java) to look for classes in the current directory (the dot).

kind regards,

Jos

Alternatively you can add the path to the directory, where the compiled Hello.class is created, to the CLASSPATH environment variable(though -cp option is the preferred approach).
For details on java classpath read the following link :
http://java.sun.com/j2se/1.4.2/docs/tooldocs/solaris/classpath.html