when to use abstract class and when to use interface?
Answer Posted / rod
an excelent answer to this question is given by the
following link http://java.sys-con.com/node/36250
apart from the fact that it treats a motor and engine as
equivalent identical items when they are distinct, one
needing elec the other petrol or steam, but the analogy
still holds and is very well illustrated.
In short we use abstract classes to reduce complexity and
duplication, whilst we use interfaces to allow changes in
design without breaking the class hierarchy.
He uses an abstract motor class as a base class to both
solar powered and battery powered vehicles. But what happens
if you must then
describe a third class of vehicle which is a hybrid of these
2 types, you cannot inherit from them both to pick up the
methods of each class so you are stuck having to break the
class hierarchy and redesign.
However If you had used interfaces, you could implement both
the battery and solar car's ability to get the charge time
and minimum light to operate respectively from multiple
interfaces.
| Is This Answer Correct ? | 12 Yes | 4 No |
Post New Answer View All Answers
Which programming language is best in future?
What is fail first in java?
Java openings 3 - 5 years, Lnt Infotech. requirements - core java, J2ee, struts, hibernate Interview Date:- 19 March 2011 Time:- 9:00 AM to 12:00 Pm Interview Location - L & T Infotech, Manapakkam, Chennai Refererral PS NO:- 291649 (Please mention this when u fill the form only then u will be considered for interview) Documents Required:- Latest Resume, Photograph and last 3 payslips Mail me on vasan2211@gmail.com once u appear for interview
What is the meaning of course?
What is the difference between class & structure?
Is array an object in java?
Which class is used by server applications to obtain a port and listen for client requests?
Write a program to reverse array in place?
What are the steps in the jdbc connection?
Is java same as core java?
What is final class?
Explain the importance of finally block in java?
what is mena by object block any what is the use of that
Is string a class?
Is main a keyword in java?