SmallThoughts - Computers, Programming Languages and Technologies

Given the following:

1.public enum Wallpaper {
2.  BROWN, BLUE, YELLOW;
3.}

Which of the following are legal?

1. enum PatternedWallpaper extends Wallpaper {
   STRIPES, DOTS, PLAIN;
   }

2. Wallpaper wp = Wallpaper.BLUE;

3. Wallpaper wp = new Wallpaper(Wallpaper.BLUE);

4. void aMethod(Wallpaper wp) {
   System.out.println(wp);
   }

5. int hcode = Wallpaper.BLUE.hashCode();

Answer: only items 2, 4 and 6 are corrects. We can´t extend or instantiate an enumeration. The item 2 is the correct way to get a enumeration reference, the item 4 shows a method receiving a enumeration reference, and finally item 6 shows a call for the hashCode() method that all enums inherit from Object.

This entry was posted on Thursday, January 11th, 2007 at 1:45 pm and is filed under java, certification, scjp, programming. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.