Java and Microsoft C#.NET web service interoperability

It isn’t always just pluging and playing when trying to integrate two systems using web services. Especially when the other end is using some ancient Java thing (ie. Axis ver. miekka & kivi) as web service framework.

Q: When calling the service using a test tool the response seems to be valid. When calling a Java web service from C# the actual call succeeds but the response object is null. What is wrong?

A: Most likely the response XML is not valid. Pay special attention to messages root element namespace. Is it there? A dirty-quick-fix can be done by subclassing the generated web service class, overriding the GetReaderForMessage method and adding the missing namespace definition using string manipulation functions.

Q: The response message says it’t encoded as UTF8 and this seems to be true (I inspected the binary message using hex editor). Still some of the non ASCII characters like Ä or Ö appear as question marks when read from deserialized response object. What is wrong?

A: It seems that the .NET Framework determines the encoding from HTTP headers. Check “Content-Type” response header. It should match the encoding used in the actual message (ie. “text/html; charset=utf-8″).