A. Repackaging-only (when target runtime supports Java ME)
B. Bytecode translation / wrapping
C. Ahead-of-time native compilation
D. Reimplementation / porting
E. Emulator-based approach
Before discussing a converter, you must understand what JAR and VXP files are. They are not interchangeable like MP4 and AVI; they represent fundamentally different execution environments. jar to vxp converter
The "screen resolution" issue mentioned earlier is a frequent point of failure. A game designed for a 240x320 screen might be unplayable on a smaller 128x160 screen because the menu buttons become invisible or unreachable after conversion. Tools: zip utilities plus a VXP packaging script