Java Web Services : Metro vs Axis

IBM has an excellent article covering the performance of Metro and Axis2 frameworks here. See how Axis2 slows when the payload is encrypted or signed. It looks like this performance hit is beyond the binding and could happen even if JAXB binding is used.

Following are excellent articles written in this series about Metro

• Introducing Metro 
• WS-Security with Metro

SOAP vs REST

This is an excellent article by David Chappell.

This article helps to understand why REST ful services are required and how the JSON format is useful for data exchange especially Ajax apps.

Understanding WSDL

This is an attempt to explain WSDL in the simplest manner

About WSDL

• WSDL stands for Web Service Definition Language.
• It is a contract to the web service that is expressed in XML. To understand better this can be compared to an Interface in Java or a Package in Oracle which acts as a contract between the client and the system.

Structure of WSDL (parallels are drawn to Java wherever possible)

1. What are the capabilities of the Service? 
• What are the operations(methods) provided by the Service and what are the messages(parameters) that each operation requires?
• The messages can be input(parameters), output(return value) or faults(exception)
2. How can the Service be accessed?
• What is the protocol(SOAP) and what is the encoding(document)?
3. Where can the Service be accessed?
• What is the endpoint(address) of the Service?

 Illustration of the WSDL Structure
The CreditService web service developed earlier is used to illustrate