JAVA

what is final in java

Final is used to apply restrictions on class, method, and variable.
The final class can't be inherited, final method can't be overridden,
and final variable value can't be changed. Final is a keyword

final in java

if a variable declared as final then no class can change its value once 
it is given a value.

final java

//allows for variables to be unchanged throught a program
final float constant = 12;
println(constant);  // Prints "12" to the console
constant += 6;  // ERROR! It's not possible to change a "final" value

final class java

You cannot extend a final class. If you try it gives you a compile time error.

final Method Java

class FinalDemo {
    // create a final method
    public final void display() {
      System.out.println("This is a final method.");
    }
}

class Main extends FinalDemo {
  // try to override final method
  public final void display() {
    System.out.println("The final method is overridden.");
  }

  public static void main(String[] args) {
    Main obj = new Main();
    obj.display();
  }
}

final Class Java

// create a final class
final class FinalClass {
  public void display() {
    System.out.println("This is a final method.");
  }
}

// try to extend the final class
class Main extends FinalClass {
  public  void display() {
    System.out.println("The final method is overridden.");
  }

  public static void main(String[] args) {
    Main obj = new Main();
    obj.display();
  }
}