The default keyword in Java programming language
In this tutorial, we will discuss The default keyword in Java programming language
The default is used in two ways in Java.
The default is used to add a default ‘case’ in switch statements in Java
The default is used to add default methods in interfaces since Java 8.
The default is an optional part of switch statements which are used only if none of the above cases is matched
Default keyword in switch statements
Declaration
The syntax of the default keyword
default;
Program
class Best_color{
public static void main (String args[]){
int colour=3;
String print_colour;
switch (colour){
case 1:print_colour="Red";
break;
case 2:print_colour="Blue";
break;
case 3:print_colour="Green";
break;
case 4:print_colour="Yello";
break;
default ://default keyword
print_colour="No selection";
break;
}
System.out.println(print_colour);
}
}
When the above code is compiled and executed, it will produce the following results
Green
default method in the interface
default keyword is used to create default method inside the interface
Declaration
The syntax of the default method in Java
default void method_name(){
//some code here
}
Example
Example of default method in Java
interface Getable{
//default method
default void getSalary(){
//some code here
}
}
//default method declaration inside the interface in Java language
Program 1
interface DemoDefault{
void myMarks();
default void display()
{
System.out.println("This is the default method");
}
}
class DefaultKey implements DemoDefault{
public void myMarks(){
System.out.println("implementation of myMarks");
}
}
public class DemoInterface{
public static void main(String args[]){
DemoDefault obj=new DefaultKey();
obj.display();
obj.myMarks();
}
}
When the above code is compiled and executed, it will produce the following results
This is the default method
implementation of myMarks
There are other Java language keywords that are similar to this keyword
float keyword in Java