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Why is there constructor in abstract method when abstract method cant me instantiated?It is confusing me..

Code from tutorialspoint.com

public abstract class Employee
 {
   private String name;
   private String address;
   private int number;
   public Employee(String name, String address, int number)
    {
      System.out.println("Constructing an Employee");
      this.name = name;
      this.address = address;
      this.number = number;
   }
   public double computePay()
   {
     System.out.println("Inside Employee computePay");
     return 0.0;
   }
   public void mailCheck()
   {
      System.out.println("Mailing a check to " + this.name
       + " " + this.address);
   }
    public String toString()
   {
      return name + " " + address + " " + number;
   }
   public String getName()
   {
      return name;
   }
   public String getAddress()
   {
      return address;
   }
   public void setAddress(String newAddress)
   {
      address = newAddress;
   }
   public int getNumber()
   {
     return number;
   }
}

Now you can try to instantiate the Employee class as shown below:

* File name : AbstractDemo.java */
public class AbstractDemo
    {
       public static void main(String [] args)
       {
  /* Following is not allowed and would raise error */
      Employee e = new Employee("George W.", "Houston, TX", 43);

      System.out.println("\n Call mailCheck using Employee reference--");
      e.mailCheck();
    }
}

When you compile the above class, it gives you the following error:

   Employee.java:46: Employee is abstract; cannot be instantiated
  Employee e = new Employee("George W.", "Houston, TX", 43);
               ^
1 error

What i m getting into trouble is if it has to show error why is their constructor in Abstract classes for what reason?

Maizere Pathak.Nepal
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1 Answers1

2

It's there for concrete subclasses to use.

class SubEmployee extends Employee {
  public SubEmployee(String name, String address, int number) {
    super(name, address, number);
  }
  ...
}
Louis Wasserman
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