You can install Multiple version of any Java Application on your s60 3rd Edition phone. This trick is tested on my 3250. Also tested on another sony erricsson phone. Works nice.
Follow these steps:
1. Open the .jar file with Decompressor like WinRar.
2. Open the Folder META-INF
3. Copy the MANIFEST.MF file to PC
4. With a text editor like Notepad, modify the MIDLET NAME/DESCRIPTION;
for example, if the orginal name is 'Opera Mini'
change the name to 'Opera Mini 1'
(You can optionally change other optins too like vendor or data-size.)
5. Save the file.
6. Rename the original MANIFEST.MF file to MANIFEST1.MF (FOR BACKUP)
7. Put back the MODIFIED MANIFEST.MF to the folder META-INF
