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Inheritance (extend): Exam questions tests - Sun Certified Java Programmer 310-065 - Lesson 60 | Java courses

In this video, we are continuing the first set of the exam questions. We start with a question that covers class inheritance (extend). One important point to remember is that you can have a parent class pointing to a child (an Employee referencing an HourlyEmployee).

Duration: 16:19 minutes

Summary: In this video, we are continuing the first set of the exam questions. We start with a question that covers class inheritance (extend). One important point to remember is that you can have a parent class pointing to a child (an Employee referencing an HourlyEmployee). But, for the other way around, you need to cast to the appropriate class. On the second question, we discuss the fact that only instance methods can be overridden, and calls to ‘super’ only apply to overridden methods. On the third question, we talk about is-a and has-a relationship. In has-a, we have a containment relationship (i.e. class A has classB). But for is-a, we are talking about inheritance (a Rectangle is-a Shape). Finally, we cover HashMaps. The trick to these questions is making sure you are using the correct method. In this case, the method ‘add’ was used instead of ‘put” which causes a compilation failure.



Senior Software Engineer with experience in C#, JavaScript, jQuery, Knockout JS, Kendo UI, HTML5, and SQL Server. Ayad has more than 20 years experience in technical training and teaching. Contributor to MrBool for about 7 years.

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