Abstract Method and Classes in Java



Yes. We can create abstract method/classes in Java very easily.

Example

To create an abstract class, just use the abstract keyword before the class keyword, in the class declaration. 

/* File name : Employee.java */
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;
   }
}

You can observe that except abstract methods the Employee class is same as the normal class in Java. The class is now abstract, but it still has three fields, seven methods, and one constructor.


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