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

abstract keyword in Java

boolean Keyword in Java

break keyword in Java

Byte keyword in Java

case keyword in Java

catch keyword in Java

char keyword in Java

class keyword in Java