A method is a named sequence of Java statements that can be invoked by other Java code. When a method is invoked, it is passed zero or more values known as arguments . The method performs some computations and, optionally, returns a value. As described in Section 2.4 earlier in this chapter, a method invocation is an expression that is evaluated by the Java interpreter. Because method invocations can have side effects, however, they can also be used as expression statements. This section does not discuss method invocation, but instead describes how to define methods.
You already know how to define the body of a method; it is simply an arbitrary sequence of statements enclosed within curly braces. What is more interesting about a method is its signature . The signature specifies the following:
The name of the method
The number, order, type, and name of the parameters used by the method
The type of the value returned by the method
The checked exceptions that the method can throw (the signature may also list unchecked exceptions, but these are not required)
Various method modifiers that provide additional information about the method
A method signature defines everything you need to know about a method before calling it. It is the method specification and defines the API for the method. The reference section of this book is essentially a list of method signatures for all publicly accessible methods of all publicly accessible classes of the Java platform. In order ...