diff --git a/lib/open3.rb b/lib/open3.rb
index 2f035e3bcd..9652b27194 100644
--- a/lib/open3.rb
+++ b/lib/open3.rb
@@ -31,12 +31,8 @@
 
 require 'open3/version'
 
-if RUBY_ENGINE == 'jruby' && JRuby::Util::ON_WINDOWS
-  require_relative 'open3/jruby_windows'
-  return
-end
-
 module Open3
+
   # Open stdin, stdout, and stderr streams and start external executable.
   # In addition, a thread to wait for the started process is created.
   # The thread has a pid method and a thread variable :pid which is the pid of
@@ -763,3 +759,6 @@ module Open3
   end
 
 end
+
+# JRuby uses different popen logic on Windows, require it here to reuse wrapper methods above.
+require 'open3/jruby_windows' if RUBY_ENGINE == 'jruby' && JRuby::Util::ON_WINDOWS
diff --git a/lib/open3/jruby_windows.rb b/lib/open3/jruby_windows.rb
index 24b9a1ba7e..064c38b597 100644
--- a/lib/open3/jruby_windows.rb
+++ b/lib/open3/jruby_windows.rb
@@ -57,6 +57,15 @@ module Open3
   module_function :popen2e
 
   def processbuilder_run(cmd, opts, build: nil, io:)
+    opts.each do |k, v|
+      if Integer === k
+        if IO == v || !(String === v || v.respond_to?(:to_path))
+          # target is an open IO or a non-pathable object, bail out
+          raise NotImplementedError.new("redirect to an open IO is not implemented on this platform")
+        end
+      end
+    end
+
     if Hash === cmd[0]
       env = cmd.shift;
     else