Object Oriented Programming OOP Concepts Inheritance in Java

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Inheritance - "is a" relationship
        - Single Inheritance
        - Multiple (level) Inheritance

Inheritance code example


Output:

//ClsCalculator objClsCalculator = new ClsCalculator();

Base class output start 
1 + 1 = 2
100.1 + 100.1 = 200.2
Base class output end 

//ClsCalculator objClsAdvCalculator = new ClsAdvCalculator();
Sub class output Start 
1 + 1 = 2
100.1 + 100.1 = 200.2
Sub class output end 

//ClsAdvCalculator objClsAdvCalculator1 = new ClsAdvCalculator();

Base + Sub class output Start 
1 + 1 = 2
100.1 + 100.1 = 200.2
Sub class output Vinod  +  kumar = Vinod  kumar
Base + Sub class output end 

ClsCalculator.java

/**

 * 
 */
package inheritance.tutorialbyexample.com.copy;

/**
 * @author Vinod Kumar
 *
 */
public class ClsCalculator {

 /**
  * Default constructor of ClsCalculator
  */
 public ClsCalculator() {
  // TODO Auto-generated constructor stub
 }

 /**
  * Addition of two number and print the value in console and return the
  * number as output.
  * 
  * @param parameter1
  * @param parameter2
  * @return
  */
 public int addition(int parameter1, int parameter2) {
  // addResult the local variable for storing the add result and used in
  // print
  // method and return.
  int addResult = parameter1 + parameter2;
  // Private method for internal use not outside of world
  print(parameter1, parameter2, addResult);
  return addResult;

 }
 
 public float addition(float parameter1, float parameter2) {
  // addResult the local variable for storing the add result and used in
  // print
  // method and return.
  float addResult = parameter1 + parameter2;
  // Private method for internal use not outside of world
  print(parameter1, parameter2, addResult);
  return addResult;

 }

 /**
  * Private method for printing the addition of input and output
  * 
  * @param arg1
  * @param arg2
  * @param argAdd
  */
 private void print(int arg1, int arg2, int argAdd) {
  System.out.println("" + arg1 + " + " + arg2 + " = " + argAdd);
 }

 /**
  * Private method for printing the addition of input and output
  * 
  * @param arg1
  * @param arg2
  * @param argAdd
  */
 private void print(float arg1, float arg2, float argAdd) {
  System.out.println("" + arg1 + " + " + arg2 + " = " + argAdd);
 }
 
}


ClsAdvCalculator.java

/**
 * 
 */
package inheritance.tutorialbyexample.com.copy;

/**
 * @author Vinod Kumar
 *
 */
public class ClsAdvCalculator extends ClsCalculator {

 /**
  * Default constructor of ClsCalculator
  */
 public ClsAdvCalculator() {
  // super();
  // TODO Auto-generated constructor stub
 }

 /**
  * Addition of two number and print the value in console and return the
  * number as output.
  * 
  * @param parameter1
  * @param parameter2
  * @return
  */
 public String addition(String parameter1, String parameter2) {
  // addResult the local variable for storing the add result and used in
  // print
  // method and return.
  String addResult = parameter1 + parameter2;
  // Private method for internal use not outside of world
  print(parameter1, parameter2, addResult);
  return addResult;
 }

 /**
  * Private method for printing the addition of input and output
  * 
  * @param arg1
  * @param arg2
  * @param argAdd
  */
 private void print(String arg1, String arg2, String argAdd) {
  System.out.println("Sub class output " + arg1 + " + " 

                 + arg2 + " = " + argAdd);
 }

}


MainAppOfCalculator.java

/**

 * 
 */
package inheritance.tutorialbyexample.com.copy;

/**
 * @author Vinod Kumar
 *
 */
public class MainAppOfCalculator {

 /**
  * Default Constructor of MainAppOfCalculator
  */
 public MainAppOfCalculator() {
  // TODO Auto-generated constructor stub
 }

 /**
  * Main method for creation the instance of {@link ClsCalculator}
  * ClsCalculator instance as object
  * 
  * @param a
  */
 public static void main(String a[]) {
  System.out.println("Base class output start ");
  // Creating the instance of ClsCalculator() class.
  ClsCalculator objClsCalculator = new ClsCalculator();
  // Calling the addition method with two int parameter
  objClsCalculator.addition(1, 1); // This is from base class
      // ClsCalculator
  // Calling the addition method with two float parameter
  objClsCalculator.addition(100.1f, 100.1f); // This is from base class
             // ClsCalculator
  System.out.println("Base class output end ");
  System.out.println("");

  System.out.println("Sub class output Start ");
  ClsCalculator objClsAdvCalculator = new ClsAdvCalculator();
  objClsAdvCalculator.addition(1, 1); // This is from sub class
        // ClsCalculator
  objClsAdvCalculator.addition(100.1f, 100.1f); // This is from sub class
              // ClsCalculator
  System.out.println("Sub class output end ");
  System.out.println("");

  System.out.println("Base + Sub class output Start ");
  ClsAdvCalculator objClsAdvCalculator1 = new ClsAdvCalculator();
  objClsAdvCalculator1.addition(1, 1); // This is from sub class
            // ClsCalculator
  objClsAdvCalculator1.addition(100.1f, 100.1f); // This is from sub class
              // ClsCalculator
  objClsAdvCalculator1.addition("Vinod ", " kumar");
  System.out.println("Base + Sub class output end ");

 }

}