Final method in java

In this section we will learn about Final method in java.

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Final method in java

In this section we will learn about Final method in java. Final  keyword in java is used with class, variable and methods. If final is used with method that method will not be overridden in subclass, if final is used with class that class cannot be inherited by subclass and if final is used with variable then that variable act like a constant, cannot be changed.

Final class :

final class A
{ }
class B extends A { }

This is a compile time error because final class cannot be inherited.

Final method :

public class FinalDemo 
{
	 public final void display()
	 {
		 System.out.println("In class FinalDemo");
	 }
}
class A extends FinalDemo
{
	 public void display() // Error Final method cannot be overridden
	 {
		 System.out.println("hi");
	 }
}

If final is used with method it cannot be overridden by subclass if doing so, it could be a compile time error.

Final variable : If a variable is declared with final keyword then the variable cannot be changed throughout the program it act like a constant.

public class FinalDemo
{
	final static int a=10;
	 public static void main(String args[])
	 {
		 a=12; // Here, compile time error final variable cannot assigned
		 System.out.println("a ="+a);
	 }
}

changing the value of a is not allowed because it is final variable you cannot change.

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