diff --git a/src/codegen/gen_java_Message.ysl2 b/src/codegen/gen_java_Message.ysl2
index b9de724..7f8854c 100644
--- a/src/codegen/gen_java_Message.ysl2
+++ b/src/codegen/gen_java_Message.ysl2
@@ -126,6 +126,8 @@ tstylesheet {
             public interface «$cname»Interface {
                 public String encodeMIME();
 
+                public String toXER();
+
                 `` apply "*[name(.)!='enum']", mode=interface
             }
             ||