There's a cost associated with 'instant'

• Complex applications typically have classes logically grouped as packages; JWS doesn't handle packages
• Data de/serialization cannot be customized
• Source code required; compiled classes cannot be exposed as services with JWS

Java packages map to directory hierarchies of classes. JWS is suitable for small standalone SOAP services that do not have complex representations or dependencies. The workaround that is to simply use JWS classes as facades for the complex data entities in your application.