Explain how a JAVA program works (sources included) - produces XML file with hashes and signature

I have a JAVA software (with sources), which takes a binary file as input, and produces XML file with signature of the input data, as output. I was told it follows this standard: PKCS#7- XAdES, No Container, Detached, BASELINE-B I need to understand what the java software does, and how does it produce the given sections in the output XML file, so I could then make a different software in different programming language to produce the same output. For example, part of the XML output is a sha256 hash, so regarding this part, your explanation should be: "this part is created by creating a sha256 hash of this input data, encoded as base64 string". This is sufficient for me as far as the functions involved have clear meaning. Your task will be to read the JAVA source codes, understand how the XML output is created, and explain that to me. I am a skilled programmer (PHP mostly), I just don't understand JAVA. The JAVA software for this particular purpose is here: Binary: [login to view URL] Source code: [login to view URL] (I was told it is based on this github project: [login to view URL] ) The output XML file is attached as [login to view URL] (with pretty-print version) The signature xml file was created this way: - run the java software [login to view URL] (it is a GUI application) - click button to select input file (attached too, as [login to view URL]) - click "Soubor na disku" (it means, file from disk) - select some signing certificate (pfx file, I can provide this), input its password - click Podepsat (it means: Sign) - save resulting xml file