Java Data Types

Data Types & Literals in Java

A data type represents the type of data we are storing into variables. The value we are storing in the variable is known as literal.

Integer:

Represent integer numbers. Integer numbers are numbers without fractional part.

Data Type	Memory Size	Min & Max values
Byte	1 byte	-128 to +127
Short	2 bytes	-32768 to +32767
Int	4 bytes	-2147483648 to +2147483647
long	8 bytes	-9223372036854775808 to +9223372036854775807

Float data type:

Float data type represents floating point numbers. Float data types are used to

handle numbers with decimal points.

Data Type	Memory Size	Min & Max values
float	4 bytes	-3.4e38 to +3.4e38
Double	8 bytes	-1.7e308 to +1.7e308

Example:

float pi = 3.14F; (by adding F JVM allocates 4 bytes otherwise JVM allocates 8 bytes.)

double distance = 1.98e8;

Difference between float and double?

float represents up to 7 digits accurately after decimal point. (single precision floating point)

double represents up to 15 digits accurately after decimal point. (double precision floating point)

Character data type:

Character data type represents a single character.

Data Type	Memory Size	Min & Max values
char	2 bytes	0 to 65535

Example:

char ch = 'x';

What is Unicode?

Unicode is a specification to include the alphabets of international languages into 

character set of java. Unicode system uses 2 bytes to represent a character.

String data type:

String data type represents a group of characters. String is also a class and We will descuss more about it in the coming lessions.

Example:

String name = "Java";

String str = new String("Java");

Boolean data type:

Boolean data type represents either true or false.

Example:

boolean response = false;