A Java multithreading demo about running 3 threads simultaneously

MultiThreadingJava.java

class Running implements Runnable {
   private Thread t;
   private String name;
   
   Running( String threadName) {
      name = threadName;
   }
   
   public void run() {
      //String name = "A";
      int sum = 0;
      for(int x = 0; x < 9; x++){
        sum += x;
        System.out.println("Thread : "+name+" - value : "+Integer.toString(x));
      }
      System.out.println("Thread : "+name+" - sum : "+Integer.toString(sum));
   }
   
   public void start () {
      if (t == null) {
         t = new Thread (this, name);
         t.start ();
      }
   }
}

class Main {
  public static void main(String[] args) {
    Running A = new Running("A");
    Running B = new Running("B");
    Running C = new Running("C");
    A.start();
    B.start();
    C.start();
  }
}