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[java] Execution flow...

Started by kino Apr 13, 2005 at 4:27 PM 3 replies 1k views

Original Post

Apr 13, 2005 at 4:27 PM

Suppose that somewhere from a class X there’s a message to an object Y which don’t return anything; Class X { …code code code Y.someMethod(); // someMethod is void type next line } Class Y { …code code code public void someMethod() { While (true) { Do anything forever!!!} } } The class X executes the “next line” or not? I’m afraid to hear a big YES, OFF COURSE!! , but that’s not what’s happening in my program… Thanks all!!

daireq

Apr 13, 2005 at 4:48 PM

I'd be surprised if it WAS happening in your program ! that while loop will execute forever unless theres a break or it throws an exception or something that knocks the execution out of the loop.

If what you want is for X to resume after the call to someMethod, you'll have to create a seperate thread for Y to run in, and start it up. In that case X will resume immediately after its started the thread and both will run concurrently.

D.

CaptainJester

101

CaptainJester

Apr 14, 2005 at 6:11 AM

In other words, the way you have it set up now, Y.someMethod() will not return.

kino

Author

kino

Apr 14, 2005 at 12:16 PM

Oops, sorry! I forget to say that Y already is a thread!
So, next line must be executed, rigth?

pirate_dau

Apr 14, 2005 at 1:51 PM

Even if Y "is a thread", if you call someMethod() from the thread which X is running in, it's going to wait for Y to return before executing the next statement.

Maybe this will explain things a bit...

public class X {    public static void main(String[] args) {        Thread thread = new Thread(new Y());        thread.start();        System.out.println("foo");        new Y().someMethod();        System.out.println("bar");    }}public class Y implements Runnable {    public void run() {        someMethod();    }    public void someMethod() {        while(true) {            // do something        }    }}

"foo" should be printed, but "bar" will not.

EDIT: Fixed source tags
EDIT: Woops, meant thread.start() and not thread.run()

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