Error: Could not find or load main class(Java)

Question

I am using java in ubuntu machine. I can run java program from my eclipse. But I have some work that that I have to perform from command prompt. I could compile java program using javac HelloWorld.java command and its create the HelloWorld.class in same directory. But when I run java HelloWorld command its gives me following error.

Error: Could not find or load main class

I dont know why???

can anyone tell me what's the problem?

Answer 1

Check you CLASSPATH. It should contain current directory (aka ".").

Answer 2

Did you correctly create a main method in your java file, did you name the java file exactly like the class?

$ cat HelloWorld.java

public class HelloWorld {

        public static void main(String[] args) {

                System.out.println("Bonjour le monde !");

        }

}

$ javac HelloWorld.java
$ java HelloWorld
Bonjour le monde !

Answer 3

I was executing

java HelloWorld.class

instead of

java HelloWorld

Problem Solved!