When a variable is declared, it is declared with a particular
type. The type tells what kind of values the variable can have,
and what the possible operations on that type are. There are
eight primitive types in Java; these are the basic building
blocks from which all other types are constructed. In addition,
Java defines literally thousands of object types, and every
program you write has additional programmer-defined object types
of its own. Every class defines a type. int is a primitive type
that can have integer values, and the operations add, subtract,
multiply, divide, and several others. an object type supplied by
Java, with operations such as substring. When you write a
program, you might define a type (class) named Employee with
operations