Can't run any application with Intellij IDEA

Question

I used to work with Intellij IDEA and at a certain moment something happened that i can't run any application anymore. The problem is that buttons 'Run' and 'Debug' (the ones that are called with Shift+F10 and Shift+F9) are inactive -

.

There are also another pair of this buttons, that are called with Alt+Shift+F10(F9), but after i click on them, i get this -

.

I tried to reinstall IDE, but that didn't help. Here the code of the application i'm trying to run, though it doesn't work with any application.

PS I'd like to add also a screenshot of the project structure, but i can't post more that 2 links, so i just do this way:

>untitled
  >idea
  >out
  >src
    >(C) WallyFinder
  untitled1.iml
>External Libraries

The code:

import java.util.regex.Pattern;
import java.util.regex.Matcher;

public class WallyFinder {

    public static int wheresWally(String str) {
        Matcher m = Pattern.compile(" Wally\\b").matcher(" " + str);
        return m.find() ? m.start() : -1;
    }

public static void main(String args){
    int a = WallyFinder.wheresWally("aaaaWally");
    System.out.println(a);
}
}

Answer 1

The directory structure is wrong I think. It should be like this

>untitled
  >idea
  >out
  >src
    >main
       >java
         >(C) WallyFinder
  untitled1.iml
>External Libraries

Can you please try this.