How to make a java program run always

[Karthikean Konangi]

Hi,

I have created a Java program which need to run always. it has to keep on running. How can i create that . Please advise.

Thanks in advance.

[Jesper de Jong]

Just create a loop in your application that never stops, and don't return from the main() method. For example:

while (true) {
    // do something ...
}

[Rob Spoor]

Not really an intermediate problem.

[Karthikean Konangi]

Thanks for all your replies.
I guess, i didnot ask the question properly.

My question is " I already wrote a Java program with infinate loop.But how can i make this job as a cron/ scheduled job / some job so that, it has to run always in the server. I should be able to start/stop the process and close the command prompt. How can i do this??

[Christopher Young]

My guess, if you're on Windows, anyway, set it [Windows] up to launch the application you need at start, or, launch a batch file that launches the application you need.

Is there a way to do this in the Java library? I don't know, as I hear it tries not to be OS-specific.

I suppose you could use the Java Native Interface, maybe. Or maybe I'm off track.
[ June 25, 2008: Message edited by: Christopher Young ]

[Jesper de Jong]

There are several ways to run Java programs as Windows services, that start when Windows starts. Search for "java windows service" on Google.

On Unix or Linux, you can add a startup script somewhere in the /etc folder to start your program at boot. How this works exactly depends on what flavour of Unix or Linux you're using (read the documentation of your OS).

[vaibhav gupta]

How about using java.util.TimerTask

A task that can be scheduled for one-time or repeated execution by a Timer.

http://java.sun.com/j2se/1.4.2/docs/api/java/util/TimerTask.html

Here is a sample code:;Hope this helps..

-Vaibhav

import java.util.Timer;
import java.util.TimerTask;
import java.util.Date;
 
public class TestScheduler 
{
public static void main(String[] args) 
{
//interval set as per your need //
long interval = 1* 60 * 1000 / 12;
 
MyScheduler scheduler = new MyScheduler();
Timer timer = new Timer();
timer.schedule(scheduler, new Date(), interval);
}
}
 
class MyScheduler extends TimerTask 
{
long initTime =System.currentTimeMillis();
 
public void run() 
{
//do something
System.out.println("do something..@ "+(System.currentTimeMillis()-initTime)/1000);
}
}

[edit]Add code tags. CR[/edit]
[ June 25, 2008: Message edited by: Campbell Ritchie ]

[Karthikean Konangi]

Thanks for your reply.

Again I have to intiate TestScheduler process and, if I close the Command Prompt the process will close automatically.

And my OS is Sun Solaris 5.8


Please advise.

[Sagar Rohankar]

search for "Quartz job Scheduler" for job scheduling . and make a simple java program which takes START OR STOP command , which in turn start/stop your job class ..

[vaibhav gupta]

You can use invoke the process in background (as you said you are using solaris os)

See: http://learnlinux.tsf.org.za/courses/build/shell-scripting/ch12s02.html

e.g.

java TestScheduler &

After this you can even close the command prompt.

[SaurabhSri Sri]

You can run a java program as a daemon process in UNIX environment by using Java Service Wrapper. Please see this url -
Java Service Wrapper

[Campbell Ritchie]

"Vaibhav g" please read your private messages again.