java.lang.NoClassDefFoundError

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Level 1

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java.lang.NoClassDefFoundError

Hi all,

I having problems running a java class.

I am using eclipse. I create a program in eclipse (hello world). It compiles and runs using eclpise ok.

The problem is when I compile it using terminal (javac command) it compiles ok, but when I try to run it (java comand) I get the following error.

java.lang.NoClassDefFoundError

I know it is a classpath issue, but I don't know what causes it or how to correct it.

Regards Wayne.

iMac 24", Mac OS X (10.5.7)

Posted on Jun 5, 2009 6:58 PM

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Answer 1

Jun 6, 2009 6:26 PM in response to WayneAnthony

Hi WayneAnthony,

Assume I have the code in Hello.java:


/*
Hello.java, simple hello world example
*/
public class Hello
{
 public static void main (String[] args)
 {
 System.out.println("Hello, World!");
 }
}

After compiling Hello.java with javac, you can run it from the command-line using

java Hello # not Hello.java or Hello.class!

So compiling and running looks like:

javac Hello.java
java Hello

Hello, World!

In this case, everything works fine. If I try to specify the full name for the 'java' command, I get the problem you mentioned:

java Hello.java

Exception in thread "main" java.lang.NoClassDefFoundError: Hello/java

java Hello.class

Exception in thread "main" java.lang.NoClassDefFoundError: Hello/class

I don't think the CLASSPATH is really causing problems in this case.

I hope that helps!
Caleb

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Answer 2

Jul 6, 2009 4:19 AM in response to Caleb Mattoon

this doesn't solve the problem since you obviously aren't using eclipse! :rolleyes:

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