java - Eclipse can't find / load main class

Question

My Eclipse (Indigo) was running just fine. I created a simple class Hello. It is placed in package cont in the folder ch13. However, when I try to run it from Eclipse I get info from Java Virtual Machine Launcher:

Could not find the main class: cont.Hello.  

I tried to run other classes from this package and they run just fine (that is the classes that existed there before). However any new class I create in this package has these problems. Actually any new class I create in Eclipse runs into this problems. I decided to check how it works from the command line. It seems that the problem still exist - I get same error. I checked the path and it is C:Program FilesJavajdk1.7.0_02in, which is correct (note the other classes are running from Eclipse just fine). I tried to run with java -cp . Hello and there are some Errors produced starting with java.lang.NoClassDefFoundError: Hello (wrong name: cont/Hello). Code itself is simple:

package cont;

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

}

How can I fix it so that my classes still run under Eclipse?

Answer 1

.metadata is corrupted.

Steps:

Warning: Deleting .metadata will delete all your Eclipse configurations, plugins, project setups. Make a backup before you attempt this!

1. Stop eclipse, delete .metadata in workspace and restart eclipse

2. Import Project

3. Run again