When to Use Exception Handling

Exception handling is designed to process synchronous errors, which occur when a statement executes. Common examples we will see throughout the book are out-of-range array indices, arithmetic overflow (i.e., a value outside the representable range of values), division by zero, invalid method parameters, thread interruption and unsuccessful memory allocation (due to lack of memory). Exception handling is not designed to process problems associated with asynchronous events (e.g., disk I/O completions, network message arrivals, mouse clicks and keystrokes), which occur in parallel with, and independent of, the program's flow of control.

Software Engineering Observation 13.2

Incorporate your exception-handling strategy into your system from the design process's inception. Including effective exception handling after a system has been implemented can be difficult.

Software Engineering Observation 13.3

Exception handling provides a single, uniform technique for processing problems. This helps programmers working on large projects understand each other's error-processing code.

Software Engineering Observation 13.4

Avoid using exception handling as an alternate form of flow of control. These "additional" exceptions can "get in the way" of genuine error-type exceptions.

Software Engineering Observation 13.5

Exception handling simplifies combining software components and enables them to work together effectively by enabling predefined components to communicate problems to application-specific components, which can then process the problems in an application-specific manner.