Not understanding "synchronized key word"

Question

Hello all,
I have a singleton class as below
package test;
public class TestClass {
    private final static TestClass testClass = new TestClass();
    private TestClass() {
        super();
        // TODO Auto-generated constructor stub
    public static TestClass getInstance() {
        return testClass;
    public  synchronized void keepRunning() {
        for (int i = 0; i < 10454564564l; i++) {
            for(int j=0 ; j<242342342342l;j++){
                System.out.println(j);
}And two other classes which take the reference and call keepRunning simultaneously as shown
package test;
public class TestClass1 {
    public TestClass1() {
        super();
        // TODO Auto-generated constructor stub
     * @param args
    public static void main(String[] args) {
        TestClass testClass = TestClass.getInstance();
        testClass.keepRunning();
}and
package test;
public class TestClass2 {
    public TestClass2() {
        super();
        // TODO Auto-generated constructor stub
     * @param args
    public static void main(String[] args) {
        TestClass testClass = TestClass.getInstance();
        testClass.keepRunning();
}Now if i run both TestClass1 and TestClass2, i can see sysouts from both the programs. I am not able to understand Why synchronized key word allowing TestClass2 to acess the code.(As there are no shared variable)

Answer 1

ohhhhhhhhhhh!!!!! Sorry ! I am ashamed of myself!! :-(