Understanding of the join method in Thread class in C # (reproduced)

When calling the join method of another thread in the first-line thread, the thread is blocked until the end of the other thread is executed, such as Java code.  

1. Using system;
3. Namespace testthreadjoin
4. {
5. Class Program
6. {
7. Static void main ()
8. {
9. System. Threading. Thread x = new system. Threading. Thread (new system. Threading. threadstart (F1 ));
10. X. Start ();
11. Console. writeline ("this is main. {0}", 1 );
12. X. Join ();
13. Console. writeline ("this is main. {0}", 2 );
14. Console. Readline ();
15. }
16. Static void F1 ()
17. {
18. System. Threading. Thread y = new system. Threading. Thread (new system. Threading. threadstart (F2 ));
19. Y. Start ();
20. Y. Join ();
21. Console. writeline ("this is F1. {0}", 1 );
22. }
24. Static void F2 ()
25. {
26. Console. writeline ("this is F2. {0}", 1 );
27. }
28. }
29. }

There are three threads processing (including the main thread). You can check the execution result. Result: This is main.1 this is f2.1 this is f1.1 this is main.2
If: annotation // X. Join (); Result: This is main.1 this is main.2 this is f2.1 this is f1.1