This is a tool for converting Java bytecode into JSON.

$ jvm2json --help
Usage: jvm2json [-s|--classfile CLASSFILE] [-t|--json JSONFILE] [-R|--reverse]

  a tool for converting between java classfile and json

Available options:
  -s,--classfile CLASSFILE the path to the classfile, - for stdin/out
  -t,--json JSONFILE       the path to the jsonfile, - for stdin/out
  -R,--reverse             input json and output a jvm class
  -h,--help                Show this help text

Both of commands convert Test.class into test.json

$ jvm2json -s Test.class -t test.json
$ jvm2json >Test.class <test.json

And both of these commands convert test.json into Test.class

$ jvm2json -R -s Test.class -t test.json
$ jvm2json -R <Test.class >test.json

A specification of the codec is available in CODEC.txt. A nice html version is incoming.

A limited usage is available using docker. The following command should just work and produce Json:

docker run --rm -i kalhauge/jvm2json:latest jvm2json <Test.class >test.json

You should also be able to run it in reverse.

docker run --rm -i kalhauge/jvm2json:latest jvm2json -R <test.json >Test.class

However, the file part of the CLI requires that you mount your filesystem.

To install the tool there are several options.

The first solution is to install from scratch using Haskell. The easiest way to do that is to download ghcup, and run the installation process, you should install 'stack'. You do not need HLS unless you want to develop on the tool.

Make sure that a new version of stack is installed. I have tested with:

$ stack --version
Version 2.11.1, Git revision c1167a6abc3f4978ccded5ba0246a57387da0e2f x86_64 hpack-0.35.2

Now you should be able to build the program, which might take some time the first time around.

$ stack build

After which you should be able to install the program using the following command.

$ stack install

And if all goes well, you should be able to see that you can run jvm2json -h and get the above help message.

To build the executable simply write:

nix build

You might get a 'ffi.h' not installed error, in this case you should consider running:

xcode-select --install

See here for more