package Threads;

public class AddThread implements Runnable{
    private volatile static int sum = 0;
    public AddThread(){
        
    }
    
    public void run(){
        {
            for(int i = 0;i<10;++i){
                int temp = sum;
                temp = temp +1;
                try{
                    Thread.sleep(20);
                }catch(InterruptedException e){
                    System.out.println(e);
                }
                sum = temp;
                System.out.println("This sum is "+ sum);
            }
        }
    }
    
    public static int getSum(){
        return sum;
    }
}

package Threads;

public class Core {
    public static void main(String[] args){
        AddThread first = new AddThread();
        AddThread second = new AddThread();
        
        Thread one = new Thread(first);
        Thread two = new Thread(second);
        one.setName("firstThread");
        two.setName("secondThread");
        
        one.start();
        two.start();
        
        while(one.isAlive()||two.isAlive()){
            
        }
        
        System.out.println(AddThread.getSum());
        
    }

}