CODEWITHSUNDEEP
javajava-native-interface
vishaln
vishaln

Reputation: 11

Java application with JNI

I am new to java and want to develop a java application which will run continuously like a server.

Is it possible in Java to develop a UI less application which will work continuously? This application should also have JNI support, so functions exported using JNI should get called from a C++ application.

Can anybody tell me the pointers to start?

Help is appreciated, thanks.

Vishal N

Upvotes: 0

Views: 694

Answers (5)

Oo.oO
Oo.oO

Reputation: 13405

Yes, you can run Java as service (daemon). You can simply run your code a "daemonize" it. This way, it will be detached from terminal sessions and will run in background.

Take a look here:

https://github.com/mkowsiak/jnicookbook/tree/master/recipes/recipeNo022

to see how you can run service inside C.

And here, to check out how to run service part in Java:

https://github.com/mkowsiak/jnicookbook/tree/master/recipes/recipeNo029

Have fun with JNI!

Upvotes: 0

JSS
JSS

Reputation: 2201

Yes you can develop UI less applications in Java.

I'll expect an application server to handle multiple requests, transactions, security, life-cycle, persistence, etc.

If answer is Yes then I will choose the Java EE route to implement your requirements. I'll implement my business model using EJB3.0 and deploy in one of the application servers i.e. Glassfish, JBoss etc. which will support all features described above without reinventing the wheel.
Note: The solution will also give flexibility to expose your remote methods using WebService, CORBA or JMS.
If answer is No then I might create my own standalone server type application which will listen on some port and communicate through some bespoke protocol.

In order to support JNI -I would expect that you'd have to write a plain JavaBean wrapper or proxy. This proxy would then be used by the JNI.

Upvotes: 1

Hannes de Jager
Hannes de Jager

Reputation: 2923

It is certainly possible to run without a UI. By the sounds of it you would like to create your Java APP as a console app and then run it as a Windows Service/Linux Daemon (You did not mention the OS). There are java service wrappers out there that lets you run your java code as a service (e.g. this one) or you could write your own.

I recommend this book to learn the JNI. Although it sounds like what you need it not really JNI but rather an interface exposed over TCP or something similar that another C++ app can use to talk to your app. JNI won't allow another process to talk to your app, it is there to extend your Java code with functionality that cannot be implemented in Java itself e.g. calling some Windows API function.

Edit:

By the way, a plain Java Hello World App like this one IS a console app: 

public class HelloWorld { 
   public static void main(String[] args) { 
      System.out.println("Hello, World");
   }
}

Upvotes: 1

Dave
Dave

Reputation: 4597

You can certainly develop a Java application without a user interface; I think most folks would agree that it's easier than developing one with a user interface.

Regarding JNI, if I understand the question, you've got it backwards; using C++ as an example, JNI lets you call C++ code from Java, not Java code from C++.

Upvotes: 0

Jigar Joshi
Jigar Joshi

Reputation: 240946

Yes.

Is it possible in Java to develop a UI less application which will work continuously?

Create a thread or code main thread that will run foreever.

This application should also have JNI support, so functions exported using JNI should get called from a C++ application.

yes , have a look at here

Upvotes: 0

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