No Class DefFoundError

[Lalit Nagalkar]

Hello every one
I am getting this exception when running any standalone application as simple as HelloWorld
it compiles correctly and I am in the same directory as the class. the class is not in any package

it has started giving this error just recently earlier it never happened. I dont know whats wrong.

Exception in thread "main" java.lang.NoClassDefFoundError: hello

please help
Thanks
lalit

[Katrina Owen]

Hi Lalit,

It looks like the kind of error that I get when I misspell the name of the class when running the application. In my case, the two most common causes are

1) I forgot to rename the class that contains the main() method, after renaming the file:

// file called: MyApp.java
 
class Test
{
    public static void main( String[] args )
    {
        System.out.println( "Hello" );
    }
}

Here, if I compile MyApp.java and then attempt to run the program, I get

Exception in thread "main" java.lang.NoClassDefFoundError: MyApp

If I try to run a program called Test (look at the name of my class), then the program will run successfully, even though I do not have a file called Test.java

2) I misspell the name of the program

// file is called MyApp.class
> java myApp
Exception in thread "main" java.lang.NoClassDefFoundError: myApp

The lowercase 'm' in 'myApp' (rather than capital 'M' of 'MyApp') was enough to cause an error.

Katrina
[ March 12, 2007: Message edited by: Katrina Owen ]

[Lalit Nagalkar]

Hello Katrina,
Your point is right, but I am not using different file name and different class name as my class is public. its the simplest app
--------
public class HelloWorld
{public static void main(String ar[])
{System.out.println("hello there");
}
}
--------
I am not a novice to Java(to some extent) and have run many other advanced programs, never getting such error.

I am not getting why , I tried reinstalling the jdk1.5.0 and all. But still its happening.. The jboss j2ee server, ant etc runs just fine,

"YES ONE THING" when apache server is run using java command through its settings it too doesnt run, it runs using "jvm".

Pleaze help someone

thanks
lalit

[Katrina Owen]

Have you tried changing the parameter to main to

...main( String[] args )

args? It might affect this.

// from your code
public class HelloWorld
{
    public static void main(String ar[])
    {
        System.out.println("hello there");
    }
}

Another issue:

Are you running this from the command line? Or are you trying to run it via an application server? If it is the latter, the server might not be able to see your code.