One Programinstance

Newbie & Debugging Questions
#1

Hello World!
I’m trying to write a server application, for which I have a few Questions. My problem is, that I only want to have one active Serverinstance running at anytime. Because I only want to use the typical console on windows or the terminal on linux to run my server, I have the problem, that I can’t get my running server instance back, when I eventually close my Terminal/console. My Question is now, that I need a way to at least contact my earlier startet Serverinstance, even if I closed its Terminal, can someone show me a way to do that? My Idea is creating ServerSocket in my running Serverinstance, so that I have a way to contact it, but because it should only accept commands from localhost I don’t know how to write it the right way, so I would like, if I there is a way without a ServerSocket out there.
Another problem is the part, where I check for another Serverinstance has anyone an idea for that?

Greetings
biro

#2

The key is to run your server as a daemon. You can either do this when invoking your program or you can create a thread and use Thread.setDaemon(true).

#3

:cranky: Please read the javadoc before you ‘help’ others.

#4

Whoops, I stand corrected. setDaemon(false).

#5

That’s the default value, so it doesn’t really change anything.

#6
#7

The point is that Daemon Threads are in no way related to Daemon Processes.

What you (probably) want is:
http://www.cyberciti.biz/tips/how-to-use-screen-command-under-linux.html

It gives you a virtual terminal that you can open/close (attach/detach) while keeping the process running.

#8

Hello,
thank you for your fast answer, but I’m not sure if that’s what I need…
I’m searching for a way to write a program that can be operated the same way as mysql on linux, as example.
When you start mysql on linuy you need the command: mysql start
One command -> One operation and it doesn’t block the terminal.
If I want to use another command on my server like getting its status I write: mysql status
One command -> One Operation

I want to implement this behavior in my server. I don’t want to have a server app that blocks my terminal full time. And I don’t want an application that I can’t operate when I close its terminal.

Greetings
biro

#9

You’re probably gonna have to use some shady Runtime.exec implementation then which is bad because debugging becomes a pain and screen just werks.

#10

Take a look at the Java Service Wrapper, which does exactly what you’re looking for.