Need some explanations regarding static Method

Question

Hello,
I have a code where a class has a static method access by other classes. This not working as I thought and I would like to understand why.
Here below is the code.
Here is a class having the static method "test"
package test;
public class StaticTest {
    public StaticTest() {
    public static void test (int i){
    while (i < 1000){
        System.out.println("i = " + i );
        i++;
}Here is the code of another class (Thread) using this static method. This Thread can be initialized with an integrer value that will be passed to the static Method.
package test;
public class ThreadTester extends Thread {
    int x;
    public ThreadTester(int i) {
        x=i;
    public void run(){
        StaticTest.test(x);
}Here is the code starting 2 Thread running in parallel and both are then calling the static method.
//start 2 thread accessing the static method.
      ThreadTester test1 = new ThreadTester(0);
      ThreadTester test2 = new ThreadTester(200);
      test1.start();
      test2.start();
...As the second thread is started with a bigger value I thought that we would only have seen few printouts from the first thread starting by 0 and then printouts starting by 200.
Here is what I thought regarding the result:
i = 0
i = 1
i = 2
i = 3
i = 200 --> startup of the second thread, x in static method is overriden (at least this is what I thought!)
i = 201
i = 202
i = 203
i = 204
i = 205
i = 206
i = 207
i = 208
i = 209
But the real result is:
i = 0
i = 1
i = 2
i = 3
i = 4
i = 5
i = 200
i = 6
i = 201
i = 202
i = 203
i = 204
i = 205
i = 206
i = 7
i = 207
i = 208
i = 209
i = 8
It seems that there is 2 instances running in parallel. I thought that it would'nt be the case with the word "Static".
Also I don't understand the result because if I use JBuilder in Optimizer mode I can see that there is only one instance of StaticTest object.
Can anyone here explain me how is that possible?
Thanks in advance for your help.
Regards,
Alain.

Answer 1

>
thread test1 creates its own stack and starts incrementing �i� starting at values 0. However, in the middle of incrementing, it gets kicked out by the OS (or JVM) into a �blocked� state to allow other threads to run. BUT before leaving the running state, test1 saves the stack state including the value of �i�.
>
Ok, now I understand, but then I have another question.
What is the difference between the code shown in my first post and the following where we create 2 instances of StaticTest class (which is not static in this case for sure).
How to decide (while coding) if it is better to use difference instances of class or not?
package test;
public class StaticTest {
    public StaticTest() {
    public void test (int i){ //Not static anymore
    while (i < 1000){
        System.out.println("i = " + i );
        i++;
}We create new instance in the Thread.
package test;
public class ThreadTester extends Thread {
    int x;
    public ThreadTester(int i) {
        x=i;
    public void run(){
StaticTest newInstance = new StaticTest(); //Create a new instance
        newInstance .test(x);
}Alain