CODEWITHSUNDEEP
javaconstructorabstract-class
user260833
user260833

Reputation: 43

abstraction in java program

Why is the output like below?

bike is created

running safely..

gear changed

because we are not calling Bike() method anywhere.

abstract class Bike {
    Bike() {
        System.out.println("bike is created");
    }

    abstract void run();

    void changeGear() {
        System.out.println("gear changed");
    }
}

//Creating a Child class which inherits Abstract class  
class Honda extends Bike {
    void run() {
        System.out.println("running safely..");
    }
}

//Creating a Test class which calls abstract and non-abstract methods  
class TestAbstraction2 {
    public static void main(String args[]) {
        Bike obj = new Honda();
        obj.run();
        obj.changeGear();
    }
}

Upvotes: 4

Views: 624

Answers (3)

shivam
shivam

Reputation: 1

you have created Honda class with a default constructor(without any formal arguments),so whenever you will make Honda class object then this will call default constructor(Honda()) and this constructor will call the parent class(Bike) default constructor and parent class constructor will print the statement "bike is created".

Upvotes: 0

Aminu Bishir
Aminu Bishir

Reputation: 111

In he Bike class, you have a constructor Bike() that prints a statement. So by default, a child class build upon the constructor of its parent class. That's why when ever you create an object of the class Bike, the print statement has to appear.

Upvotes: 3

Ori Marko
Ori Marko

Reputation: 58882

Honda class is created with Default Constructor

If a class contains no constructor declarations, then a default constructor with no formal parameters and no throws clause is implicitly declared.

 public class Point {
      int x, y;
 }

is equivalent to the declaration:

public class Point {
      int x, y;
      public Point() { super(); }
 }

So Bike() is called every call to new Honda();

Upvotes: 7

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