Why Both Threads Printing their own variable x value.

[Punya Pratap Singh]

public class Testing{
		
		 public static void main(String[] args){
		  ThreadGroup squares = new ThreadGroup("Squares");
		  Thread t1 = new Thread(squares, new T(), "t1"); 
		  Thread t2 = new Thread(squares, new T(), "t2"); 
		  t1.start(); 
		  t2.start();
			  		  
		 }
		}

		class T implements Runnable{
			int x = 7;
		 private int square; 
		 
		 public  void run(){
		  for(int i = 1; i < 5; i++){
			  
			  System.out.println("Value Of Int   "+ x);
		   square = i * i; 
		   x++;
		  }
		 
		 } 
		}

In this Example when both threads are running they are printing their own values of variable x,I consider that if variable x is a global varibale for the class, then if one thread makes from x=7 to x= 8 then second thread should consider x=8,but it is considering it x=7 why ?

Please Expalin.

[NK: Added code tags. Please UseCodeTags while posting code]

[Christophe Verré]

new T() means a new instance of T. So you have two new instances of T, each with its own instance variable. x is an instance variable of T. It's not static. Another instance of the same class won't interfere with it.

[Punya Pratap Singh]

Thanks Christope Understood.

Then how can we create Dirty Data read problem in this Example.
Means if one thread makes x= 8 then next one should read it like x= 8 not 7.
please show me the way in the same example.

Thanks.

[Christophe Verré]

By using the same instance ?

T t = new T();
Thread t1 = new Thread(squares, t, "t1");
Thread t2 = new Thread(squares, t, "t2");