Default and Initial Values in Java 

The XSD standards tell you how to handle default values. The following standard procedure exists for proxy generation:

Standard Procedure for Default Handling

Client proxy	When generating the XML data stream, the default value is set in all initial fields.
Server proxy	Inbound processing of the proxy runtime sets empty and missing tags to the default value before the application is called.

To improve performance, optional, initial, scalable elements without a default value are suppressed in the message.