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Objects and Collections

sri rallapalli
Ranch Hand

Joined: Mar 15, 2005
Posts: 88
in K&B book,
page no:18, of Objects and Collections chapter, figure says that LinkedHashMap is not an instance of HashMap.
But in the following example, it is showing that LinkedHashMap is an instance of HashMap.

import java.util.*;
class GFC111 {
public static void main (String[] args) {
Object m = new LinkedHashMap();
System.out.print((m instanceof Collection)+",");
System.out.print((m instanceof Map)+",");
System.out.print(m instanceof HashMap);
Please Calrify my Doubt. I want to know whether the figure in K&B book is wrong or correct.
Henry Wong

Joined: Sep 28, 2004
Posts: 20365

According to the Javadoc, the LinkedHashMap class does indeed inherit from the HashMap class.


Books: Java Threads, 3rd Edition, Jini in a Nutshell, and Java Gems (contributor)
Bert Bates

Joined: Oct 14, 2002
Posts: 8898

How did I miss that one

Just finishing up the errata list - so far 5 confirmed errata, and about 5 good suggestions...

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ak pillai
Ranch Hand

Joined: Feb 11, 2006
Posts: 288
public class LinkedHashMap extends HashMap implements Map

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I agree. Here's the link:
subject: Objects and Collections
It's not a secret anymore!