This tutorial will help us to see the use of final keyword with a method of a class and a class individually.

Example:

class parentClass {

   public function test1() {
       echo "This is test1 method of parentClass";
   }

   final public function test2() {
       echo "This is test2 method of parentClass that is made final";
   }
}

OUTPUT: 
$obj = new parentClass();
$obj->test2();

//This is test2 method of parentClass that is made final 

// But when we extend the parentClass

class childClass extends parentClass { public function test2() { echo "on overriding the final method test2 a fatal error will be thrown "; } }

OUTPUT: It gives a Fatal error

When we make a class final

final class parentClass {
   public function test1() {
       echo "This is test1 method of parentClass";
   }


   public function test2() {
       echo "This is test2 method of parentClass";
   }
}


class ChildClass extends parentClass {

}

Here we get a Fatal error as we cannot extend the final class.