Question

I am trying to run a java program from command line. I tried following the steps mentioned here. But when I try to run javac Hello.java, it’s throwing error that such a program is not there. I tried giving java Hello.java and got the error:

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

What is the problem here. How can I do it?

EDIT: I have many classes in my code file, Hello.java. Will that cause any problem?

Answer 1

To run the program you need to do:

java Hello

which is java followed by the class name without extension.