Design Patterns Java™ Workbook

Exceptions in Methods

A method header may declare that the method throws exceptions. An exception in Java is an instance of any subclass of Throwable, including the Exception class and the Error class. Note that the word exception refers to an instance of Throwable but not necessarily to an instance of Exception. Figure 20.3 shows part of the Throwable hierarchy.

Figure 20.3. Of the classes shown, only Throwable, Exception, and IOException must be handled.

Exceptions are normally checked, meaning they must be declared by a method that might throw them. The Error class and its subclasses and the RuntimeException class and its subclasses are unchecked, ...