Joining threads

[Shiva Shankar]

Can any one explian the step by step flow of this program?
I was wondering how Can we change the value of final variable i?

public class Joining {
static Thread createThread(final int i, final Thread t1) {
Thread t2 = new Thread() {
public void run() {
System.out.println(i+1);
try {
t1.join();
} catch (InterruptedException e) {
}
System.out.println(i+2);
}
};
System.out.println(i+3);
t2.start();
System.out.println(i+4);
return t2;
}
public static void main(String[] args) {
createThread(10, createThread(20, Thread.currentThread()));
}
}

Output:
23
21
24
13
11
14
22
12

Thanks in advance...

[Shiva Shankar]

I got the point we are not modifying final variable i we are just using that i in System.out.println();