/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package debugoff;

import static java.lang.System.out;
 /**
 *
 * @author alice
 */
public class Debugoff {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
       Debugoff.debug();
    }
    
     public static String debug(){
        String pippo;
        pippo="Errore";
        return pippo;
        }
    
}

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package debugoff;

import static java.lang.System.out;
 /**
 *
 * @author alice
 */
public class Debugoff{
 
     public static String debug(){
        String pippo;
        pippo="Errore";
        return pippo;
        }
    
}

Update Debugoff.java