Question

I am currently using Ubuntu 11.10 and java SE 1.6.0_26. I am trying to run a very simple “Hello World” app. I placed the the java file HelloWorld.java on the Home folder. I compiled it using the command javac HelloWorld.java. I think its working because it doesn’t show any compilation error and a HelloWorld.class is created.

When I typed the command java HelloWorld I have this error:

Exception in thread "main" java.lang.NoClassDefFoundError: HelloWorld
Caused by: java.lang.ClassNotFoundException: HelloWorld
        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
Could not find the main class: HelloWorld.  Program will exit.

BTW, here is my java code:

public class HelloWorld {
    public static void main (String args[]) {
        System.out.println("Hello World!!!");
    }
}

Answer 1

It could be that the file is not in your classpath..try the following command:

java -classpath . HelloWorld

V