question about "synchronized"

[jsmitha2009]

public class TestSynchronize implements Runnable {
    int b = 100;

    @Override
    public void run() {
        try {
            method1();
        } catch (Exception e) {
            System.out.println("oops,,,, ");
        }
    }

    public synchronized void method1() {
        b = 1000;
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            System.out.println("Method - 1 Interrupted.");
        }
        System.out.println("M1: b = " + b);
    }

    public synchronized void method2() {
//        b = 2000;
        try {
            Thread.sleep(1500);
        } catch (InterruptedException e) {
            System.out.println("Method - 2 interrupted.");
        }
        b = 2000;
//        System.out.println("M2: b = " + b);
    }

    public static void main(String[] args) {
        TestSynchronize ts = new TestSynchronize();
        Thread t = new Thread(ts);
        t.start();

        ts.method2();
        System.out.println("main b = " + ts.b);
    }

}

The question I have is:

the output will be different depends on LINE 31, and why?

For example, if comment out line 31, the result will be

main b = 1000
M1: b = 1000

if leave line 31, the result will be

M2: b = 2000
main b = 2000
M1: b = 1000

Can anyone help? Thanks at advance!

[jsmitha2009]

Can anyone help, please?

[Norm]

Line 31 is a println(). It does nothing as a comment.

My output (with time):
main b = 1000 1337106415891
M1: b = 1000 1337106420899

method1() can execute between the execution of lines 39 & 40