How many threads are running?

Question

here's the code... i am trying to understand, at each point, how many threads are running:
I understand that one thread belongs to the caller of the start()
& at the same time there is another thread belonging to the instances of each thread (thread1, thread2, thread 3 etc.)
1public class ThreadTester {
2   public static void main( String args[] )
3   {
4      PrintThread thread1, thread2, thread3, thread4;
5
6      thread1 = new PrintThread( "thread1" );
7      thread2 = new PrintThread( "thread2" );
8      thread3 = new PrintThread( "thread3" );
9      thread4 = new PrintThread( "thread4" );
10
11      System.err.println( "\nStarting threads" );
12
13      thread1.start();
14      thread2.start();
15      thread3.start();
16      thread4.start();
17
18      System.err.println( "Threads started\n" );
19   }
}can you tell me if i am counting the number of threads in existance correctly...
LINE#.....CALLER...START...TOTAL THREADS
13..............1.........1.......2
14..............1+1......1+1.....4
15..............2+1......2+1.....6
16..............3+1......3+1.....8
so by the time line 16 executes i have a total of 8 threads,
4 threads belonging to each caller plus
4 threads created by start()
or is it
LINE#.....CALLER...START...TOTAL THREADS
13..............1........1........2
14..............1........1+1.....3
15..............1........2+1.....4
16..............1........3+1.....5
after line 16 executes does the caller thread die, thus leaving only a total of 4 threads?
there is only one thread belonging to the caller at line 13(plus the thread it creates).
at the start of line 14, the previous callers thread is dead & now a new thread is created that belongs to the caller on line 14... etc.

Answer 1

well, i realize at the end there would be 4 threads but im trying to get my head around this explanation in the book:
"A program launches a threads executioin by calling the threads start method, which in turn call the run method. After start launches the thread, start returns to tis caller immediately. The caller then executes concurrently with the lauched thread." there fore if i have 2 concurrent processes, are there 2 threads running????
now having said the above, my question was:
for each line,
how many threads are in existance at
line13
line14
line15
line16
thanks.