java_gen: cleanup / preparations for Match
diff --git a/java_gen/templates/of_interface.java b/java_gen/templates/of_interface.java
index b969d50..186b787 100644
--- a/java_gen/templates/of_interface.java
+++ b/java_gen/templates/of_interface.java
@@ -35,7 +35,7 @@
//:: include("_imports.java", msg=msg)
-public interface ${msg.name} ${"extends %s" % msg.parent_interface if msg.parent_interface else ""} {
+public interface ${msg.name} extends OFObject${", %s" % msg.parent_interface if msg.parent_interface else ""}{
//:: for prop in msg.members:
${prop.java_type.public_type} get${prop.title_name}()${ "" if prop.is_universal else " throws UnsupportedOperationException"};
//:: #endfor