symbian application as background process

Question

is it possible to create java application that will work as background process on symbian smartphones?

Answer 1

You can approximate it but J2ME (the version of java on mobile phones) may not be the right technology to do this.

• starting a MIDlet (a Java application for mobile phones) when the phone is switched on is tricky at best without coding a small Symbian OS C++ module that will start it for you. If you want to try anyway, look at the PushRegistry class in the MIDP specs (http://java.sun.com/javame/reference/apis/jsr118/). The Content Handling API might provide some way to do it too (http://java.sun.com/javame/reference/apis/jsr211). When you are ready to give up, do it in C++.

• Backgrounding a MIDlet isn't hard. The phone's "menu" key will do it for you. Programatically, Canvas.setCurrent(null) has a good chance of working. Trying to trick the phone by providing a fully transparent GUI and not handling any keypad activity will absolutely not work. Creating and starting a separate Thread in the MIDlet should allow you to keep something running even after your overload of MIDlet.pauseApp() has been called by the application management system.

• The real issue is that the MIDlet will not have any Inter Process Communication system unless you make one. The usual way of doing that is a loopback socket connection over which you transfer data. Not a nice or efficient way of simulating IPC. Sharing a RMS record can only be done from within the same MIDlet suite (you can package several MIDlets into the same .jar file), I think. The code to create a provider/consumer data flow over a file connection is even uglier and will raise security issues.

Without any more information about what you want to use it for, my answer is : maybe but you should probably not try.

Answer 2

You will have in-built MIDP support for background MIDlets in MIDP 3.0 (http://jcp.org/en/jsr/detail?id=271). Don't hold your breath for devices to appear, however - might be some time. (Note that a few Symbian OS devices have more than just MIDP - the S-E p990 for instance, https://developer.sonyericsson.com/site/global/products/phonegallery/p990/p_p990.jsp).

As already pointed out, it might be helpful to have more information on what product functionality you are trying to implement - often more than one way to skin a cat.