Tip Bank

DevX - Software Development Resource

Multi-dimensional Arrays

Question: Can I create multi-dimensional arrays in JavaScript? Do you have an example? Answer: Yes and no. You can’t create multi-dimensional arrays (as such) in JavaScript. What you can do

DevX - Software Development Resource

Selecting Three Radio Buttons

Question: I want to validate a form so that three radio buttons may be checked, but no more. This will be used in a “what are your top three choices”

DevX - Software Development Resource

EJBs and Servlets

Question: Both Enterprise JavaBeans and Servlets are server side components. What are the major differences between them? Specifically, what is the difference between a Session Bean and a Servlet? Answer:

DevX - Software Development Resource

Interface vs. Abstract Class

Question: What is the difference between an interface and an abstract class? Answer: Within the confines of Java syntax, an interface is a type that only defines abstract methods and

DevX - Software Development Resource

Mouse Position

Question: Can I retrieve the position of the mouse on the screen? I need to know the X and Y coordinates because I want to position a layer at that

DevX - Software Development Resource

File Deletion

Question: I’m opening a file for reading, and after reading its contents I write it all to other file. Now I want to delete the original file. How do I

DevX - Software Development Resource

Use of SocketImpl Class

Question: What is the SocketImpl class used for? Answer: SocketImpl is an abstract class that provides an interface for customizing socket implementations. Subclasses of SocketImpl are not intended to be

DevX - Software Development Resource

Threads and JDBC Connections

Question: Is the JDBC Connection class thread safe? In other words, can a connection be shared between multiple threads without using synchronization? Answer: java.sql.Connection is actually an interface and not

DevX - Software Development Resource

Project Reference

Question: In a code I’m developing, I am getting a “can’t find project or library” error message when it gets to the following functions: Chr(), Right(), Left(). Aren’t these VB