Variables In Java-Types of variables with examples

Variables In Java-Types of variables in java with examples

Variables are defined by giving the name of data types before the variable. In Java, variables must be defined prior to their use. A variable stores values of data types .A variable has a particular size and a value associated with it. In Java, variables can only store values of primitive data types and references to object. Java defines the three types of variables. Each variable can store values of primitive data types or references to objects only.

1. Local variable(method automatic variable) —> These are the variables  declared within a method. These are directly accessed. 

2. Static variable(class variable) —> memory allocated only once. These variables declared using static keyword. These are directly accessed. 

3. Instance variable —> These are the variables declared inside the class. These are similar to local variable. Accessing is done through object

Default values for member variables

• If static variables in a class are not explicitly initialized, then when the class is loaded they are initialized to default value.

• Instance variables are also initialized to default values  when the class is instantiated, unless they are explicitly initialized to some value

• A reference variable is initialized to the value null

• Local variable are not initialized

Different type varible declaration and printing program

Class Variable{

static  int age=25;             // static variable

int ID=498;                   // instance variable 

public static void main(String args[]){

String name=”Habiba”;     // local variable

System.out.println(name); // Habiba printed

System.out.println(age);    // 25 printed

Variable object1=new Variable(); // object creation

System.out.println(object1.ID); // 498printed

}

}

data type in java

Different type variable declaration and printing program in eclipse IDE