IT Job Interview » Object-Oriented http://www.it-job-interview.com Face IT, Answer IT, Get IT! Thu, 18 Nov 2010 16:35:42 +0000 en hourly 1 http://wordpress.org/?v=3.0 What Is Polymorphism and How It Is Implemented in Java? http://www.it-job-interview.com/polymorphism-java.html http://www.it-job-interview.com/polymorphism-java.html#comments Sun, 06 Aug 2006 21:18:08 +0000 admin http://www.it-job-interview.com/?p=56 This is fundamental question about object oriented design and programming. To answer correctly, you must be clear about the concept of overload and override. To make a perfect answer, you may give an example of how overload and override are used in Java. The following is a sample answer:

“Polymorphism refers to overload and override features in object oriented design. Overload is implemented by define multiple methods with the same name but different arguments. For example, getContractNum(String agencyNum) may overload getContractNum(). Override is implemented by defining the same method with the same signature in the derived class but may execute different functions from the parent class. Override is often used to included more functionalities in the constructors in the derived class.”

]]> http://www.it-job-interview.com/polymorphism-java.html/feed 0 What is a Garbage Collector? How it is Used? http://www.it-job-interview.com/garbage-collector.html http://www.it-job-interview.com/garbage-collector.html#comments Thu, 03 Aug 2006 05:41:30 +0000 admin http://www.it-job-interview.com/?p=47 Again, this is a very basic, but detailed question about object oriented languages. You may also be asked to describe the advantages and disadvantages of using garbage collector, or how it is used in a specific language such as C++ or Java. Here I just give you some basic concepts of garbage collector:

Why garbage collector is needed? – When an object is no longer referenced by another object, then it is necessary to reclaim the system resources such as cache memory previously allocated by this object. A garbage collector periodically scans the active object space for objects no longer being referenced and released the system resources for any such objects.

Advantages – This automatic process relieves the application programmer from the duties of freeing objects that are no longer needed. This represents a substantial saving in the amount of detailed, low-level programming that the programmer must do.

Disadvantages – The garbage collection process is typically not under control of the application. This can lead to unpredictable delays in processing.

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