Investigate! Directions: Type each of the following statements into your main method. Test them one-by-one, commenting each one out when you're done with it. For each one, (i) write the output or write "compiler error"; (i) explain why you got the output you did, or why you got an error. System.out.println (mary.getSalary()): System.out.println (jill.getLanguage ()) ; System.out.println (mary.tostring ()): System.out.println (bob.tostring ()); Worker tl - bob; Worker t2 - mary: System.out.printin (t1.getSalary (); System.out.println (t2.getLanguage (); Programmer jane - new Programmer ("Jane", "Python", 47000) ; Worker temp - jane; temp.raisesalary (30000); System.out.println (temp.getsalary ()):

public class Worker {
 private String name;
 private double salary;

 public Worker(String aName, double sal) {
  name = aName;
  salary = sal;
 }

 public String getName() {
  return name;
 }

 public double getSalary() {
  return salary;
 }

 public void work() {
  System.out.println("Employee working");
 }

 public void raiseSalary(double byAmount) {
  salary += byAmount;
 }

 public String toString() {
  return name + " has a yearly salary: " + salary;
 }

}

public class Programmer extends Worker {
 private String programmingLanguage;

 public Programmer(String aName, String lang, double sal) {
  super(aName, sal);
  programmingLanguage = lang;
 }

 public String getLanguage() {
  return programmingLanguage;
 }

 public void work() {
  System.out.println("Programmer working");
 }

 public String toString() {
  return "Programmer: " + super.toString() + " and programs in " + programmingLanguage;
 }
}

public class Manager extends Worker {

 public Manager(String aName, double sal) {
  super(aName, sal);
 }

 public void work() {
  System.out.println("Manager working");
 }

 public String toString() {
  return "Manager: " + super.toString();
 }
}

public class Main {
 public static void main(String[] args) {
  Worker bob = new Worker("Bob", 15000);
  Programmer mary = new Programmer("Mary", "Java", 70000);
  Manager jill = new Manager("Jill", 56000);
  /*
   * Note : before compiling this we need to comment jill.getLanguage() and
   * t2.getLanguage() as there is a compiler time error and the reason is stated
   * below
   * 
   * Output: 70000.0 this is because Mary is an object of class Programmer which
   * is a subclass of Worker Worker class has a method getSalary which Programmer
   * class can use because of inheritance value 70000 was set in the field salary
   * at the time of object creation through constructor using super we passed
   * 70000 but the output is 70000.0 because the data type is double.
   */
  System.out.println(mary.getSalary()); // returns 700000

  /*
   * Output: compiler error
   * 
   * There is a compile time error because jill is an object of class Manager
   * which does not have the method getLanguage. It is present inside class
   * Programmer.
   */
//  System.out.println(jill.getLanguage());

  /*
   * Output: Programmer: Mary has a yearly salary: 70000.0 and programs in Java
   * 
   * First toString() method of Programmer class is called which created a string
   * starting with 'Programmer: ' and ending with ' and programs in Java' it calls
   * the toString() method of its super class Worker which adds the string 'Mary
   * has a yearly salary: 70000.0' in between the earlier two strings.
   */
  System.out.println(mary.toString());
  /*
   * Output: Bob has a yearly salary: 15000.0
   * 
   * toString() method of Worker class is called which created a string 'Bob has a
   * yearly salary: 15000.0'.
   */
  System.out.println(bob.toString());

  Worker t1 = bob;
  Worker t2 = mary;

  /*
   * Output: 15000.0
   * 
   * t1 and bob are pointing to the same address therefore they point to the same
   * object which has the name 'Bob' and salary '15000'
   */
  System.out.println(t1.getSalary());
  /*
   * Output: compiler error
   * 
   * There is a compile time error because although t2 is same as mary which is a
   * programmer t2 is a variable of class Worker and Worker class does not have a
   * method getLanguage(). to make the below line work we can write
   * System.out.println(((Programmer) t2).getLanguage());
   */
//  System.out.println((t2.getLanguage());

  Programmer jane = new Programmer("Jane", "Python", 47000);
  Worker temp = jane;
  temp.raiseSalary(30000);
  /*
   * Output: 77000.0
   * 
   * an Object of class Programmer is created which has salary 47000
   * temp points to this same object
   * using method raiseSalary() from class Programmer salary increased from 47000 to 77000
   * temp using getSalary() method from the parent class Worker prints the salary.
   */
  System.out.println(temp.getSalary());
 }
}