iPhone / iPad CalDav Debugging

I've build and application that uses caldav in Java. It works fine with iCal and other CalDav client but I can't seem to get it to work on iphone/ipad. The consol debugger in xCode is not very explicite about what the problem is. Is there any tool around to help me debug what my application is doing wrong?

More information. The server side is running Java with a servlet and tomcat. T开发者_开发知识库he client side is the Apple Caldav support on iphone / ipad. I use xcode to see the consol of the phone. I get error codes like: DAVErrorDomain/30. What ever that means it somewhere but I can't find any good info about apple's error codes anywhere. Any idea?

The iPad/iPhone does not support Java, so likely XCode is complaining about this fact?