Java.util

text zoom

Previous: HashSet Collection Framework File and Directory Permissions in JDK1.6 :Next

It contains the collections framework, legacy collection classes, event model, date and time facilities, internationalization, and miscellaneous utility classes (a string tokenizer, a random-number generator, and a bit array). Some of the Enhanced Collections Framework are described below:

Enhanced Collections Framework - The Collections Framework has these new convenience APIs:
- Added Collections.singletonList and Collections.singletonMap.
  
  Previously, there was a convenience implementation for singleton Set, but no corresponding implementation for List and Map. Both of these implementations proved desirable in practice.
- Added Collections.EMPTY_MAP.
  
  Previously, there were constant convenience implementations for the empty Set and List, but no corresponding implementation for Map.
  
  The following special-purpose implementation has also been added:
- Added Map constuctor for WeakHashMap. The Map interface dictates that most Map implementations should have a "copy constructor" that takes a Map argument. WeakHashMap lacked such a constructor in the 1.2 release.

Let's take an example of java.util collection.

import java.util.*;

public class SetExample {

public static void main(String args[])

{

    Set set = new HashSet();

    set.add("Bernadine");

    set.add("Elizabeth");

    set.add("Gene");

    set.add("Elizabeth");

    set.add("Clara");

    System.out.println(set);

    Set sortedSet = new TreeSet(set);

    System.out.println(sortedSet);

}

}