about System: currentTimeMillis()

hello,
i am new in java,
i wrote a java program, my program is multiplication of two big matrixes and i used 10, 50 ,200, 1000 treads in it to execute. but when i computed the endtime-starttime of my program for each number of threads, i had increasing numbers according to the increasing number of threads.
i used "currentTimeMillis()".
for example:
10 threads==> 266
200 threads ==> 2484
1000 threads ==> 12549
why did i meet this result,
my computer in not multicore and i was expecting decreasing numbers according to increasing number of threads?

Why do you think that multiple threads decrease time? And how are you measuring time?

first, thank you for you interested my problem,
i dont know if it is true, but i had an expectation that if we used multiple threats, the computation would finished earier because we divided the jop to parts, and
i used:

Code:

---

  " long startTime = System.currentTimeMillis();
          mainclass ext=new mainclass();
          ext.islemler();
    long endTime = System.currentTimeMillis();
    System.out.println(endTime-startTime); "

---

in detail,

islemler is:

Code:

---

public void islemler(){
            "for(int x=1;x<=1000 ;x++)
/*    1,10,50,100,200,500,1000==> thread    number, we can change it if we want to do it by 1,10,50,100,200,500,1000 threads by replacing these numbers, here now there is "1000".*/
            {      ThreadClass t;Thread a;
                        t=new ThreadClass(x,1000);
                            a=new Thread(t);
                            a.start();
                           
            }

---

Multi-threading per se cannot speed up computer processing, since each thread shares a bit of processor time and will slow the other down. The exception to this is with a multiple processor environment if the problem can be split into parallel non-dependent processes, and even then, there's no guarantee that Java and the OS will run things on different processors.

thank you :)