Static methods Every Java program in this book is either a data-type definition
(which we describe in detail in Section 1.2) or a library of static methods (which we describe
here). Static methods are called functions in many programming languages, since
they can behave like mathematical functions, as described next. Each static method is
a sequence of statements that are executed, one after the other, when the static method
is called, in the manner described below. The modifier static distinguishes these methods
from instance methods, which we discuss in Section 1.2. We use the word method
without a modifier when describing characteristics shared by both kinds of methods.