Getting Started - Absolute Java - page 16

Java has basic types for characters, different kinds of integers, and different kinds of
floating-point numbers (numbers with a decimal point), as well as a type for the values
true and false . These basic types are known as primitive types . Display 1.2 shows
all of Java's primitive types. The preferred type for integers is int . The type char is
the type for single characters and can store common Unicode characters. The preferred
type for floating-point numbers is double . The type boolean has the two values true
and false . (Unlike some other programming languages, the Java values true and
false are not integers and will not be automatically converted to integers.) Objects of
the predefined class String represent strings of characters. String is not a primitive
type, but is often considered a basic type along with the primitive types. The class
String is discussed later in this chapter.

primitive
types

Assignment Statements
The most direct way to change the value of a variable is to use an assignment
statement . In Java, the equal sign is used as the assignment operator . An assignment
statement always consists of a variable on the left-hand side of the assignment operator
(the equal sign) and an expression on the right-hand side. An assignment statement
ends with a semicolon. The expression on the right-hand side of the equal sign may be
a variable, a number, or a more complicated expression made up of variables, numbers,

assignment
statement

assignment
operator

Display 1.2 Primitive Types

MEMORY
USED TYPE NAME KIND OF VALUE SIZE RANGE

boolean

true or false

1 byte Not applicable

char Single character

(Unicode)

2 bytes Common Unicode characters

byte

Integer 1 byte - 128 to 127

short

Integer 2 bytes - 32768 to 32767

int

Integer 4 bytes - 2147483648 to 2147483647

long

Integer 8 bytes - 9223372036854775808 to

9223372036854775807

float

10 +38 to Floating-point

number

4 bytes ; 3.40282347 *

10 -45 ; 1.40239846 *

double

;1.76769313486231570 * 10 +308 to
;4.94065645841246544 * 10 -324

Floating-point
number

8 bytes