Java and SOAP

Chapter 7. Faults and Exceptions

The difference between good software and bad software is often the way in which errors and problems are handled. It’s much easier to deal with processes when everything is working properly than it is to deal with failures. Structured and object-oriented programming provide lots of techniques for handling errors. Methods often return a special value, like null or -1, to indicate an error of some kind. In Java, methods frequently throw an exception indicating that something unusual has occurred. Good software is written to expect certain types of errors, and is prepared to take appropriate action. In SOAP terminology, these unusual, or exceptional, circumstances are called faults. Faults occur whenever a service method is not able to process input parameters and return results properly. There are endless reasons why this may occur. Common problems that result in faults are bad method parameter values, back-end problems, and improperly formatted SOAP request messages. I’m sure you can think of plenty of others, and have probably had to write code to deal with them. In this chapter we’ll look at the mechanisms for generating and handling faults in SOAP.

Throwing Server-Side Exceptions in Apache SOAP

The most common way for a service to generate a fault is to throw an exception. Apache SOAP has a mechanism for handling exceptions thrown from the Java class methods that implement service methods. The information in the exception is used to generate ...