Static Variable:
- Defining a variable inside the class and outside to methods.
- Static variable must define with static keyword.
- Static Variable access using Class-Name.
| class Bank { static String bankName = “AXIS”; } |
Note: We always process the data (perform operations on variables) using methods.
Getter and Setter Methods:
- set() method is used to set the value to variable.
- get() method is used to get the value of variable.
- Static variables : process using static set() and get() methods
- Instance variables : process using instance set() and get() methods
| class Code { static int a; static void setA(int a){ Code.a = a; } static int getA(){ return Code.a; } public static void main(String[] args){ Code.setA(10); System.out.println(“A val : ” + Code.getA()); } } |
Static variables automatically initialized with default values based on datatypes:
| Datatype | Default Value |
| int | 0 |
| double | 0.0 |
| char | Blank |
| boolean | false |
| String | null |
| class Code { static int a; static double b; static char c; static boolean d; static String e; public static void main(String[] args) { Code.values(); } static void values() { System.out.println(“Default values : “); System.out.println(“int : ” + Code.a); System.out.println(“double : ” + Code.b); System.out.println(“char : ” + Code.c); System.out.println(“boolean : ” + Code.d); System.out.println(“String : ” + Code.e); } } |
It is recommended to define get() and set() method to each variable in the class:
| class First { static int a, b, c; static void setA(int a){ First.a = a; } static void setB(int b){ First.b = b; } static void setC(int c){ First.c = c; } static int getA(){ return First.a; } static int getB(){ return First.b; } static int getC(){ return First.c; } } class Second { public static void main(String[] args) { First.setA(10); First.setB(20); First.setC(30); System.out.println(“A val : ” + First.getA()); System.out.println(“B val : ” + First.getB()); System.out.println(“C val : ” + First.getC()); } } |