Single Inheritance for Classes in Java

What happens when we try to overload the constructors in the sub class (for that matter, even in the super class)?  The following gives you the solution. 

Modify your “second.java” as follows:

  public class Second extends First {

    /** Creates a new instance of Second */
    public Second() {
        x = 90;
        y = 80;
    }

    public Second(int m, int n) {
        x=m;
        y=n;
    }

    public int getProduct() {
        int p;
        p = x * y;
        return p;
    }
}

Modify your “test.java” so that it looks something like the following:

  private void btnShowActionPerformed(java.awt.event.ActionEvent evt) {
  // TODO add your handling code here:
        Second obj1 = new Second(100, 200);
        int r;
        r = obj1.getSum();
        this.lblMsg.setText("Sum = " + String.valueOf(r));
        r = obj1.getProduct();
        this.lblMsg2.setText("Product = " + String.valueOf(r));

    }       

When you execute the program now, it will give you the output based on the values 100 and 200.  I leave it for you to understand the logic behind this.

The entire code for this article is freely available in the form of a zip file.  That downloadable solution was developed using the NetBeans 4.1 IDE together with Microsoft Windows 2003 Standard Edition. I didn’t really test it in any other version or platform.  Please follow the respective platform documentation to get it working. This series is dedicated for the beginners who wanted to work with NetBeans IDE.

Any doubts, bugs, errors, suggestions, feedback etc. are highly appreciated at jag_chat@yahoo.com.