Run time Type Identification example

In this example we shall show you how to check a type identification in run time. To check a type identification in run time we have performed the following steps:

• We have created a class A, with two methods a1() and a2().
• We have also created a class B that extends A that overrides the inherited method from A class and also has two methods b1() and b2().
• We create a new A object and a new B object and put them in an A array.
• For both fields in the array we call the a1() and a2() methods. Since B class extends A and overrides its methods, we can call them in the B object,

as described in the code snippet below.  

package com.javacodegeeks.snippets.core;

package methodoverloading;

class A {

    public void a1() {
    }

    public void a2() {
    }
}

class B extends A {

    @Override
    public void a1() {
    }

    @Override
    public void a2() {
    }

    public void b1() {
    }

    public void b2() {
    }

    public void b3() {
    }
}

public class RunTimeTypeIdentification {

    public static void main(String[] args) {

  A[] x = {new A(), new B()};

  x[0].a1();

  x[1].a2();

  // Compile time: method not found in Useful:

  //x[1].b1();


  ((B) x[1]).b1(); // Downcast/RTTI

  //((MoreUseful) x[0]).u(); // Exception thrown
    }
}

  
This was an example of how to check a type identification in run time in Java.