【DataStructure】Charming usage of Set in the java

In an attempt to remove duplicate elements from list, I go to the lengths to take advantage of methods in the java api. After investiagting the document of java api, the result is so satisfying that I speak hightly of wisdom of developer of java language.Next
I will introduce charming usage about set in the java.

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import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
public class SetUtil
{
public static List<String> testStrList = Arrays.asList("Apple", "Orange",
"Pair", "Grape", "Banana", "Apple", "Orange");
/**
* Gets sorted sets which contains no duplicate elements
*
* @time Jul 17, 2014 7:58:16 PM
* @return void
*/
public static void sort()
{
Set<String> sortSet = new TreeSet<String>(testStrList);
System.out.println(sortSet);
// output : [Apple, Banana, Grape, Orange, Pair]
}
public static void removeDuplicate()
{
Set<String> uniqueSet = new HashSet<String>(testStrList);
System.out.println(uniqueSet);
<span style="font-family: Arial, Helvetica, sans-serif;">// output : </span><span style="font-family: Arial, Helvetica, sans-serif;">[Pair, Apple, Banana, Orange, Grape]</span>
}
public static void reverse()
{
Set<String> sortSet = new TreeSet<String>(testStrList);
List<String> sortList = new ArrayList<String>(sortSet);
Collections.reverse(sortList);
System.out.println(sortList);
// output : [Pair, Orange, Grape, Banana, Apple]
}
public static void swap()
{
Set<String> sortSet = new TreeSet<String>(testStrList);
List<String> sortList = new ArrayList<String>(sortSet);
Collections.swap(sortList, 0, sortList.size() - 1);
System.out.println(sortList);
output : [Apple, Orange, Grape, Banana, Pair]
}
public static void main(String[] args)
{
SetUtil.sort();
SetUtil.reverse();
SetUtil.swap();
SetUtil.removeDuplicate();
}
}