Question: Will unlocking my phone let me play these games?

schyler523 — Mon, 21 Apr 2008 11:07:18 -0800

I have a LG Trax phone, which uses java for games and apps. I downloaded some java games made specifically for this phone from a website, then transferred them to the phone with bluetooth. The phone will not recognize these .jar or .jad files as files it can use. Will unlocking my phone fix this problem?

I have found some discussion on this matter by googling around. They mention that the various carriers only accept certain java certificates or signed java games and apps. I couldn't find any discussion about workarounds or ways to get by this 'locking' of the phone or whether 'unlocking' the phone could fix this.
I'm wondering if the hivemind has had any experience or any luck getting around this.

By: paulsc

paulsc — Fri, 09 May 2008 10:15:48 -0800

I doubt the carrier locking on your phone is the source of your difficulty. Here's a brief explanation of mobile phone Java support circa September, 2007: Java Development on Mobile Phones. The LG Trax CU575 is JST 118/MIDP 2.0 compliant, and for all the benefits of MIDP 2.0, you do get the MIDP 2.0 "horns" along with those benefits, in the form of the end to end security model of MIDP 2.0. Unless your .jar file has a X.509 PKI security certificate that can be properly verified at time of installation over your phone's network, it's never going to run. This has nothing to do, technically, with whether your phone is locked to one carrier network, or not. As an example, MIDP 1.0 games, although technically "backwards compatible" don't generally have X.509 certs, and so they are "jailed" as "untrusted" by MIDP 2.0 automatically, and many won't run, although they call no network resource.

The other thing to consider carefully is that unlocking your phone can cause it not to work on many networks, at all. On others, you can only get roaming level services. If you're considering unlocking it, have a chat with your current carrier, who can advise you about this. They may charge you a fee to do it, which can be pretty steep if you got the phone on a contract buy down, but at least when they are done, your phone should still be in their device database as a recognized unlocked device, and you shouldn't have problems.

Comments on: Will unlocking my phone let me play these games?

Question: Will unlocking my phone let me play these games?

By: paulsc