source: https://github.com/jruby/jruby/blob/master/COPYING

JRuby is Copyright (c) 2007-2018 The JRuby project, and is released
under a tri EPL/GPL/LGPL license. You can use it, redistribute it
and/or modify it under the terms of the:

  Eclipse Public License version 2.0
    OR
  GNU General Public License version 2
    OR
  GNU Lesser General Public License version 2.1

bytelist (http://github.com/jruby/bytelist),
jnr-posix (https://github.com/jnr/jnr-posix),
jruby-openssl (https://github.com/jruby/jruby-openssl),
jruby-readline (https://github.com/jruby/jruby-readline),
psych (https://github.com/ruby/psych),
yydebug (https://github.com/jruby/jay-yydebug/)
are released under the same copyright/license.

