Variables and Data Types - Learn Java - Free Interactive Java PDF | US Computer Academy

Variables and Data Types in JavaVariable

Variable is name of reserved area allocated in memory. its value can be changed

There are

Three types of variables in java:

Ø Local

Ø Instance

Ø static.

.

1) Local Variable

A variable which is declared inside the method is called local variable.

2) Instance Variable

A variable which is declared inside the class but outside the method, is called instance variable . It is not declared as static.

3) Static variable

A variable that is declared as static is called static variable. It cannot be local.

We will have detailed learning of these variables in next chapters.

Example to understand the types of variables in java

 class A{ 

 int data=50;//instance variable 

 static int m=100;//static variable

 void method(){ 

 int n=90;//local variable 

 } 

 }//end of class 

Data Types in Java

Data types represent the different values to be stored in the variable.

There are

Two types of data types in java:

Ø Primitive

Ø  non-primitive.

Data Type                  Default Value                   Default size
boolean	false	1 bit
char	'\u0000'	2 byte
byte	0	1 byte
short	0	2 byte
int	0	4 byte
long	0L	8 byte
float	0.0f	4 byte
double	0.0d	8 byte

Why char uses 2 byte in java and what is \u0000 ?

It is because java uses Unicode system than ASCII code system. The \u0000 is the lowest range of Unicode system. To get detail explanation about Unicode visit next page.