Question

Programming Questions:

1) How do you build an array of objects of a superclass with its subclass objects?

2) How do you use an enhanced for-loop to traverse through an array while calling a static method(superclass x)?

3) How do you create a static method for a class that has the parent class reference variable?

**Include java coding examples for each question if possible

Answer 1

Note : I provided the answers for the three questions which u have asked for..I mentioned the question numbers in comment section. Thank You

/*********************************************/

/******* Employee.java ******/

public class Employee extends Person {
   private double salary;

   public Employee(String name, int age, double salary) {
       super(name, age);
       this.salary = salary;
   }

   /**
   * @return the salary
   */
   public double getSalary() {
       return salary;
   }

   /**
   * @param salary
   * the salary to set
   */
   public void setSalary(double salary) {
       this.salary = salary;
   }
  
   public static void display(Person p)
   {
       Person.display(p);
       System.out.println("Age : "+p.getAge());
   }

}

/*********************************************/

/*********************************************/

/****** Person.java ******/

package org.students;

public class Employee extends Person {
   private double salary;

   public Employee(String name, int age, double salary) {
       super(name, age);
       this.salary = salary;
   }

   /**
   * @return the salary
   */
   public double getSalary() {
       return salary;
   }

   /**
   * @param salary
   * the salary to set
   */
   public void setSalary(double salary) {
       this.salary = salary;
   }
  
   /*
   * 3. Static method which is having super class reference variable
   */
   public static void display(Person p)
   {
       Person.display(p);
       System.out.println("Age : "+p.getAge());
   }

}

/*********************************************/

/*********************************************/

/******** Test.java ********/

public class Test {

   public static void main(String[] args) {

       /*
       * 1. Creating an array of sub class objects
       * which is holding by super class reference variable
       */
      
       Person emps[] = { new Employee("Mike", 23, 50000),
               new Employee("Williams", 29, 66000),
               new Employee("James", 28, 34000) };

       /*
       * 2. Iterating over the array using the enhanced for loop
       */
       for(Person p : emps)
       {
           Employee.display(p);
           System.out.println("__________________________");
       }
   }

}

/*********************************************/

/*********************************************/

Output:

/*********************************************/