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Conversion of different Collection data types

Implementations of the Collection interface normally have a constructor that accepts a Collection object. This enables you to convert a Collection to a different type of Collection, such as a Queue to a List, or a List to a Set, etc. Here are the constructors of some implementations: public ArrayList (Collection c)      public HashSet (Collection c)      public LinkedList (Collection c) As an example, the following code converts a Queue to a List. import java.util.ArrayList; import java.util.LinkedList; import java.util.List; import java.util.Queue; public class MainClass {   public static void main(String[] args) {     Queue queue = new LinkedList();     queue.add("Hello");     queue.add("World");     List list = new ArrayList(queue);     System.out.println(list);   } } [Hello, World] And this converts a List to a Set. import java.util.ArrayList; import java.util.HashSet; import java.util.List; import java.util.Set; public class MainClass {   public static void main(String[] args) {     List myList = new ArrayList();     myList.add("Hello");     myList.add("World");     Set set = new HashSet(myList);     System.out.println(set);   } } [World, Hello]