Eclipse Error: Could not find or load main class [duplicate]

Question

Have Googled extensively on this error, but I can't seem to fix the problem. I've written a basic java program in Eclipse Juno, as follows:

public class HelloWorld {      /**      * @param args      */      public static void main(String[] args) {         System.out.println("Hello Eclipse!");     }  } 

After clicking Run, I get: "Error: Could not find or load main class HelloWorld". This error message applies to all my other projects in the same workspace. I've tried switching workspaces but the error still appears.

I'm on Windows 7 64-bit. Any help would be appreciated!

Answer 1

This just happened to me today after updating my JRE. I cleaned the project and it started working again.

Project -> Clean will remove any existing class files and completely rebuild the project. There's more information on Eclipse's clean function here.