java problem

efus · 09-16-2008, 03:37 AM

I need to do some java programming, so I installed openJDK.
The code compiles fine, but when I try to run it I get this error:

Code:

Exception in thread "main" java.lang.NoClassDefFoundError: HelloWorld
Caused by: java.lang.ClassNotFoundException: HelloWorld
	at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:323)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:268)
	at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:336)
Could not find the main class: HelloWorld. Program will exit.

I get this error with openjdk and sun jdk?
anyone know how to fix this?

harry2006 · 09-16-2008, 08:28 AM

from the error log it seems u r code is incomplete....some class definiton is missing...have a walk-thur of ur code....must be something missing....if u r stillhaving problem....reply with ur code...lets have a look over ur code..tehn it'll be easy fro nyone so say whats the issue...
was ur installation OK...all jar files added properly to the library...???

armanox · 09-16-2008, 11:04 PM

Looks like a hello world program. Send me it and I'll look it over - it looks like a problem with the source.

efus · 09-17-2008, 05:53 AM

I don't think it's the source.
The source looks lige this

Code:

public class HelloWorld {
  public static void main(String[] args) {
    
  }
}

and it still gives the error.
It is only on this system I get the error.
Other java apps run fine so I asume the java installation is ok.

elprawn · 09-17-2008, 06:00 AM

Add . to your $CLASSPATH.

efus · 09-17-2008, 02:56 PM

this is my CLASSPATH

Code:

/usr/lib/jvm/java-1.6.0-openjdk/lib:/usr/lib/jvm/java-1.6.0-openjdk/jre/lib:/usr/lib/jvm/java-1.6.0-openjdk/lib:/usr/lib/jvm/java-1.6.0-openjdk/jre/lib

where sould I put the . ?

elprawn · 09-17-2008, 03:53 PM

Code:

usr/lib/jvm/java-1.6.0-openjdk/lib:/usr/lib/jvm/java-1.6.0-openjdk/jre/lib:/usr/lib/jvm/java-1.6.0-openjdk/lib:/usr/lib/jvm/java-1.6.0-openjdk/jre/lib:.

efus · 09-18-2008, 03:37 AM

Great! It works now. Thank you!

peeths003 · 09-18-2008, 08:04 AM

This is because the JVM was not able to locate your HelloWorld.class file . if you are in the directory of the class file . and you add a . against the classpath , the jvm adds the current directory path and finds your class name .