diff --git a/lib/httpx/extensions.rb b/lib/httpx/extensions.rb
index 110fac1f..000f02d9 100644
--- a/lib/httpx/extensions.rb
+++ b/lib/httpx/extensions.rb
@@ -55,26 +55,35 @@ module HTTPX
   end
 
   module URIExtensions
-    refine URI::Generic do
-      def authority
-        port_string = port == default_port ? nil : ":#{port}"
-        "#{host}#{port_string}"
-      end
+    URI_KLASSES = case RUBY_ENGINE
+    when "jruby"
+      [URI::Generic, URI::HTTP, URI::HTTPS]
+    else
+      [URI::Generic]
+    end
 
-      def origin
-        "#{scheme}://#{authority}"
-      end
+    URI_KLASSES.each do |klass|
+      refine klass do
+        def authority
+          port_string = port == default_port ? nil : ":#{port}"
+          "#{host}#{port_string}"
+        end
 
-      def altsvc_match?(uri)
-        uri = URI.parse(uri)
-        self == uri || begin
-          case scheme
-          when 'h2'
-            uri.scheme == "https" &&
-            host == uri.host &&
-            (port || default_port) == (uri.port || uri.default_port)
-          else
-            false
+        def origin
+          "#{scheme}://#{authority}"
+        end
+
+        def altsvc_match?(uri)
+          uri = URI.parse(uri)
+          self == uri || begin
+            case scheme
+            when 'h2'
+              uri.scheme == "https" &&
+              host == uri.host &&
+              (port || default_port) == (uri.port || uri.default_port)
+            else
+              false
+            end
           end
         end
       end