Today the programming question is a simple one about jumping out of loops. I think for the most part it's possible to write loops without the need for a break statement but sometimes it's convenient to do so.

The following program does not contain examples of well written loops or ones that need a break statement. It's purpose is to get you thinking about how the break statement changes the logical flow of the code: Read more...

This week the programming task was focused on creating formatted Strings using the System.out.printf method.

More specifically you had to use the printf method to create formatted strings that display Math.PI to:

• match the output of

  System.out.println(Math.PI);

• only have two decimal places
• have two decimal places and a positive sign (i.e., "+")
Read more...

Seeing as the last few articles on object-oriented programming have focused on what inheritance is and how it can be used in Java, it seems a good time to recap on inheritance for the Java term of the week.

Inheritance is a way of defining an "is-a" relationship between a class and a more specialized version of that class. For example, if a Student class extends a Person class, then it should be the case that Student is-a Person. The subclass Student builds on the functionality of the superclass Person.

Most classes will never be extended by another class. After all, inheritance is only useful when the right relationship between two classes exists and extending the functionality of a class is beneficial.

However, if a class you design might be used by other programmers it's important to consider the implications of any subclasses they create. It might the case that you do not want your class to be extended by another. Find out how to prevent your classes from being inherited.