Explain why aliases can cause trouble for programmers who are not aware of them.

-

Explain why aliases can cause trouble for programmers who are not aware of them.

Answer:  Aliases arise in Java when variables refer to the same object.  If one of those variables is used to pass a message to the object in such a way that the object is changed, then the other variables now refer to a changed object.  Unless the programmer is careful, he/she may not realize that a change has been made to the object.  Consider a class Foo that has an instance data x and a method incr that adds one to x.  Assume a and b are both of type Foo, where a’s x is 10.  Consider the following two instructions:  b = a;  b.incr( );  The result is that a/b’s value x is now 11, but if the programmer is not aware of the aliasing, then he/she might expect a’s x to still be 10.

Comments

Post a Comment

Popular posts from this blog

JAD Advantages and Disadvantages

-
JAD Advantages and Disadvantages : Compared with traditional methods, JAD is more expensive and can be cumbersome if the group is too large relative to the size of the project. Many companies find, however, that JAD allows key users to participate effectively in the requirements modeling process. Read:  What is JAD and how are users involved? What are advantages and disadvantages of JAD? When users participate in the systems development process, they are more likely to feel a sense of ownership in the results, and support for the new system. When properly used, JAD can result in a more accurate statement of system requirements, a better understanding of common goals, and a stronger commitment to the success of the new system. More:  RAPID APPLICATION DEVELOPMENT
Read more

What is JAD and how are users involved? What are advantages and disadvantages of JAD?

-
What is JAD and how are users involved? What are advantages and disadvantages of JAD? Joint application development, is a popular fact finding technique that brings users into the development process as active participants. Users have a vital stake in the information system, and should participate fully in the development process. They are/should be involved at every stage of development. Advantages : Users can participate effectively in the requirements modeling stage. More accurate statement of systems requirements, better understanding of common goals and stronger commitment to success of the new project Disadvantages : More expensive, can be cumbersome if the group is too large for the project.
Read more