Java Source Code – Is the Source Code of jar.exe Available?

I really doubt this will work. You might be able to translate your code into Java byte code, but it will not magically translate library calls into equivalent calls to the Java runtime and libraries. There may not even be equivalent Java runtime calls! Even if you eliminate all proprietary libraries you're still left with the C++ standard library.

To make this concrete: your C++ program may contain a call to fprintf(). That function is implemented in the C standard library and it's perfectly legit for a C++ program to call it. The LLVM to LLJVM translator is probably not going to magically figure out the sequence of Java run time calls that will produce the equivalent result to fprintf() and substitute those in. To provide that facility would require essentially reimplementing the C and C++ runtimes in Java byte code.

There are some tools that perform C++ to Java translation but they only convert a handful of the simpler runtime library calls. The rest are left to you to figure out.

Swarm, Spring Boot, Dropwizard - they're just microcontainers, instead of packaging your app as a war and running that in a container you are packaging the AS tooling inside your app.

There's a good comparison here: https://github.com/simundi/micro-containers