diff --git a/logstash-core/lib/logstash/patches/resolv.rb b/logstash-core/lib/logstash/patches/resolv.rb
index 2bf7d33fd04..0d74900801b 100644
--- a/logstash-core/lib/logstash/patches/resolv.rb
+++ b/logstash-core/lib/logstash/patches/resolv.rb
@@ -14,6 +14,10 @@
 
 # The code below is copied from JRuby 9.1.16.0 resolv.rb:
 # https://github.com/jruby/jruby/blob/9.1.16.0/lib/ruby/stdlib/resolv.rb#L775-L784
+#
+# JRuby is Copyright (c) 2007-2017 The JRuby project, and is released
+# under a tri EPL/GPL/LGPL license.
+# Full license available at https://github.com/jruby/jruby/blob/9.1.16.0/COPYING
 
 class Resolv
   class DNS