Final Keyword in Java | Example

→ final keyword is keyword this is non-access modifier.

Use of Final Keyword

There are there way use that is ..

Final Variable
Final Method
Final Class

1) Final Variable in Java

→ When it is initialized, we can not change the value of final variable so it is constant.

Example:-

class FinVarEx{  
 final int speedlimit =80; 
 void run(){  
     speedlimit=120; 
System.out.println("speed is " +speedlimit); 
 }  
 public static void main(String args[]){  
 FinVarEx obj=new  FinVarEx();  
 obj.run();  
 }  
} 

Output:- Compile Time Error

Example2:-

class FinVarEx{  
 int speedlimit =80;  // remove final
 void run(){  
     speedlimit=120; 
System.out.println("speed is " +speedlimit); 
 }  
 public static void main(String args[]){  
 FinVarEx obj=new  FinVarEx();  
 obj.run();  
 }  
} 

Output:-

2) Final Method in Java

→ If you want to make any method as final, you can not override .

Example:-

class Bike{  
  final void run()
   {
   System.out.println("running");
   }  
}  
     
class Honda extends Bike{  
   void run(){System.out.println("running safely with 100kmph");}  
     
   public static void main(String args[]){  
   Honda honda= new Honda();  
   honda.run();  
   }  
}  

3) Final Class in Java

→ If a class is declare by a final keyword, it cannot be extended(inherited), because show Compile Time Error. that is called Final Class.

Example1:-

final class Student{
}    
class Teacher extends Student{  
  void run(){
  System.out.println("running 1km");
}      
  public static void main(String args[]){  
  Teacher t= new Teacher();  
  t.run();  
  }  
}  

Output

Compile Time Error