In cygwin, Java parameters need to use the Windows path

[KnightCS]

• In cygwin, the variable s:jar_path is ~/.vim/plugged/vim-slumlord/plantuml.jar, if java to work properly, s:jar_path should like c:\**\.vim\plugged\vim-slumlord\plantuml.jar.
• Similarly, the variable tmpfname should also be converted into a windows path.

I modified as follows:

if has("win32unix") || has("win64unix")
    let s:jar_path = substitute(system('cygpath -w "'.s:jar_path.'"'), "\n", '', '')
    let tmpfname   = substitute(system('cygpath -w "'.tmpfname.'"'), "\n", '', '')
endif

let cmd = 'java -jar "'.s:jar_path.'" -charset utf-8 -tutxt "'.tmpfname.'"'

This works fine on my PC and hope you can fix this problem.