Hello @magician.kim
Seems to be an issue with your korean encoding, as far as I have seen searching a bit, jruby doesn't support that encoding jruby supported enconding list.
I have search a bit more and it may work changing your codepage in that terminal/cmd with chcp command
Please could you try the following?
chcp 65001
logstash-plugin list
65001 seems to be the codepage for UTF8 according to https://ss64.com/nt/chcp.html
I dont use korean enconding so I'm not able to reproduce the issue and help you better.
I hope this help 