exe2jar

Recover .jar files and launcher metadata from Java application .exe files.

exe2jar unpacks Jar2Exe and install4j/exe4j Windows launchers into usable .jar files and restore metadata.

Features

• Restore: unpack the .exe into .jar files and launcher information.
• Rebuild: create a new .exe from an existing .exe and a replacement .jar.

Usage

Install from PyPI:

pip install exe2jar

Inspect an .exe:

$ exe2jar inspect game.exe
path: game.exe
format: Jar2Exe
size: 7,896,046
config: offset=0x76ea00 size=117
tail_loader: offset=0x76ea89 size=102,757 digest=fc92cddf7ff10154eb3bf5f5aa8a538b
rc_data: offset=0x7d828 size=7,277,729 mode=l3
serial: 000102757t2845x
mainclass: com.riot.main.Main
jre_order: bcsie
jre: ./bin/
libs: bin/lib/libs
app_jar: size=3,412,924 entries=1,901

Restore .jar files:

$ exe2jar restore game.exe
[restore] mode=l3 entries=1901
[restore] L3 AES entry decrypt: 1900
[restore] classes: 1841
[restore] protected classes (J2EMAP): 57
[restore] resources: 2
[restore] restored jar: game_restored/app.jar
[restore] map:          game_restored/restore-map.json

$ ls game_restored
app.jar
jar2exe-config.json
restore-map.json

Restore outputs:

• app.jar: the recovered application jar.
• jar2exe-config.json: the parsed Jar2Exe launcher configuration.
• restore-map.json: class and resource name recovery metadata.

Rebuild a Jar2Exe .exe with a replacement .jar:

$ exe2jar rebuild game.exe game_restored/app.jar -o game_mod.exe
[build] repacked app.jar entries to Jar2Exe hash names: 1,901
[build] prepared app.jar: 3,411,574 bytes
[build] encrypted jar: 3,411,574 bytes (mode=l3)
[build] digest: 2cf193e28fc3f9dd70760d60d3ba941d
[build] output: game_mod.exe (4,029,934 bytes)

$ ls game_mod.exe
game_mod.exe

Development

uv sync --group dev
uv run python -m unittest discover -s tests
uv build --no-sources

Disclaimer

exe2jar is intended for research and authorized analysis only. Do not use it to violate software licenses, bypass access controls, or redistribute proprietary application files without permission. You are responsible for complying with applicable laws and license terms.

License

MIT