error 'Exception in tread "main" java.lang.NOClassDefFoundError: programname

Posted on 2001-09-05
Last Modified: 2007-12-19
I get this error when I compile my program.  Please tell me how to resolve it.
Question by:tinav
  • 4
  • 4
LVL 27

Expert Comment

ID: 6457694
Please give more information.
Show us your code, and show us what you are typing at command line.
LVL 19

Expert Comment

by:Jim Cakalic
ID: 6457696
When you compile (javac) or when you run (java)?

Author Comment

ID: 6458134
Sorry about that.  When I compile (javac), it compiles without error.

When I run it lfrom ms_dos like: java Swing_Sample, I get the error.

The program is:
import javax.swing.UIManager;
import java.awt.*;

public class Swing_Sample1 {

  public Swing_Sample1() {
     DisplayFramejr myframe = new DisplayFramejr();
     Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
     Dimension frameSize = myframe.getSize();
     if (frameSize.height > screenSize.height) {
       frameSize.height = screenSize.height;
     if (frameSize.width > screenSize.width) {
       frameSize.width = screenSize.width;
     myframe.setLocation((screenSize.width - frameSize.width) / 2, (screenSize.height - frameSize.height) / 2);
  public static void main(String[] args) {    
     new Swing_Sample1();
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LVL 27

Expert Comment

ID: 6458202
You said
>When I run it lfrom ms_dos like: java Swing_Sample, I get the error.
Don't you mean to enter Swing_Sample1

Author Comment

ID: 6458287
Yes, sorry again. I giess I am still new at this.  I say:
> java Swing_Sample1
and I get error
'Exception in tread "main" java.lang.NOClassDefFoundError:  Swing_Sample1
LVL 27

Expert Comment

ID: 6458798
Is Swing_Sample1.class  in your classpath?
Do you have it in your working directory?
Tell us more about how you are doing things,step by step.

Author Comment

ID: 6459037
I think you are on the right track.  Maybe the classpath variable is not setup right because, I just  found out that I get this message for every program that I compile and run.  All compile fine and don't run.  

I am using jdk1.3.1_01 that I just downloaded and I have my programs in a directory called java and I cd to that directory and say:

C:\java\java Swing_Sample1

The class files are already created in the directory.  Someone told me to go to the bin directory of JDK and run it there.  I moved my programs thare and it didn't make any difference.

Can you tell me what path and classpath variables needs to be for jdk1.3.1?

LVL 27

Accepted Solution

rrz earned 200 total points
ID: 6459154
I don't know which system you are working on , but for Win98
SET JAVA_HOME=C:\jdk1.3.1

If you put it in C:\jdk1.3.1_01 then use that instead of jdk1.3.1

Author Comment

ID: 6461017
Thanks.  I typed in the exact same thing for those three variables and it worked.

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