Open the .jar with an archive tool (7-Zip/WinRAR). Look for a folder called META-INF and a file MANIFEST.MF. Inside, you must see lines like:
MIDlet-Name: MyApp
MIDlet-Version: 1.0
MIDlet-Vendor: Example
If these are missing, your .jar is not a mobile app and cannot become a .vxp.
Check Device Compatibility:
Many modern VRE-based phones reject unsigned VXPs. Use the VXPSignerUPD.exe tool:
> VXPSigner my_app.vxp -cert test.cer -key test.key
Old tutorials used Cygwin. The UPD method uses MinGW-w64 with ARM-none-eabi-gcc. Run the VRE builder: Convert .jar To .vxp UPD
> vre_make.bat TARGET=my_app
If successful, this outputs a <project>.vxp file.
For most users, downloading desktop software isn't necessary. Several online tools have been updated to handle this specific conversion. Open the
Steps:
Note: If the online converter fails, proceed to Method 2. If these are missing, your