Java and Database Connectivity

A bit about syntax: declaring a class

public final class BlobHand extends Hand
{
    int radius;         // the radius of my blob

• public means that any other class in any other package may use this class
  • it might be protected (only usable by other classes in the same package)
  • or private (only usable by other classes in the same file)
• final means that no class may specialise ('extend') this class
  • most classes are not final
• class means it's a class
• BlobHand is the name of this class
• extends Hand means that a BlobHand is a kind of Hand, and inherits all Hand's behaviours and properties
• radius is an instance variable of BlobHand. Every instance (object) in the BlobHand class has a radius. It doesn't have to be the same radius.
• A public class must be declared in a file whose name is the same as the name of the file (with the extension '.java'. So the class BlobHand must be declared in a file called BlobHand.java

Full text of this presentation | Table of Contents | No Frames Author: Simon Brooke | Copyright © 1998-1999 Weft Technology Ltd Slide 32 of 92