* Potential fix for the multi-sources not being generated properly
As described here https://www.infoworld.com/article/2071275/when-runtime-exec---won-t.html under "Listing 4.2 BadExecJavac2.java" the limited buffer size of the standard input associated with the sub-process can cause problems with the Runtime exec method.
Consuming what the sub-process outputs should in theory allow for the process to finish (+ if you enable log level debug we could get some nice debug information in the future).
I've tested this on my local machine and it works there, please do not accept the PR with this commit before the Github checks pass successfully and I've looked further into this.
* Multi-sources not being generated properly - ErrorStream redirect
Now redirecting the errorStream of the sub-process to the standard output of the subprocess, so that we can consume it with the `javaProcess.inputStream` stream.
arkon