[Tutorial] Basic java Modding Tutorial for free gprs for all..

Do you want to modify java apps by yourself using your phone?

Here are tools that you need if you want to modify a java application (ie, Opera Mini, etc.).

1. X-Plore (1.42):

File Manager that is used to extract jar archives and edit manifest.mf’s.

2. Zntxhan (2.04):

File Editor that is used to edit .class files and other files. There are also other files that are supported by zntxhan. (python needed)

3. Image Designer (1.40):

Image Editor that is used to edit or create image files for icons, skins and etc of a java file. (python needed)

4. JarBoom (2.0):

Compiler that is used to compile or pack the extracted java archive. Using this doesnt give me an authorization failed error upon installing the packed jar. (python needed)

Thats it! For a basic need, that was enough. For python based apps, you need the python installer and the module pack to run those apps.

For other s60 such as s60v3. There are also corresponding apps for your phone version of the said apps on same name

or s40, I havent tried it yet but it was possible though I see it a little harder. And we will not settle on that. ;P

I hope you get a little idea about the apps. Up next is the detailed and step by step tutorial on how to modify java apps

We will now start on the basic of modding. I will teach you how I learned this stuff. So the sharing knowledge process is Shankru's way. *credits goes to my mentors and other people that gave me knowledge about modding Ankitkumarpal,jbpsedu,faishaln73,handler and {your_name_here} So let’s proceed.

1.Preparing the java file:

for example we want to modify an Opera Mini 5 final, we use xplore to locate it, click it and we see a lot of files. All we had to do is to extract all files in JarBoom’s unjar folder using X-plore.

2.Editing the Manifest:

Look for META-INF folder and inside you will see a MANIFEST.MF file. You can edit it with X-Plore by pressing [8]. Edit the necessary details you want to change (ie, MIDlet-Vendor, MIDlet-Version, MIDlet-Name, MIDlet-Info-URL, MIDlet-Description and MIDlet-1). Make sure when saving, the Save as unicode option is NOT
checked.

3.Editing the Class Files:

Using Zntxhan, locate any .class file via Listway. We need to edit these to change the server and put a trick on it. In Opera Mini 5 final the server is located in f.class (this differs on every java apps). You can use the functions of Zntxhan to search for the string of the server in the class. After editing, save and delete the created .class_bak (which serves as backup but we do not need this)

4.Editing the Icon:

Here we will use ImageDesigner, you can edit the i.png file that was extracted to any design you like, just make sure you made it small to fit in as an icon, 50is enough (I guess).

5.Compiling:

After we had edited what we needed to, we’re off to compiling the files back into jar file again. In this case, we will use JarBoom, choose Tools-Compile and locate the manifest.mf inside meta-inf folder and give name to your jar file, wait until the packing completes.

That’s it! Try your modded om. If it installs, great! You did it. This is all just for now, I hope you get a little idea about modding and we will proceed to deeper topics in future. Always note that, what I post here was based on my knowledge about this topic. We may have our own style or way. Explore and you will learn.

have a good day everyone!