sort array of string, reverse order using Comparator

package collection.sort;

import java.util.Arrays;
import java.util.Comparator;

public class SimpleArraySorting {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		String[] names={"US", "China", "Japan", "Germany"};
		Arrays.sort(names); 
		showArray(names);//China, Germany, Japan, US
		Arrays.sort(names, new ReverseOrder());
		showArray(names); //US, Japan, Germany, China
		
	}

	public static void showArray(String[] a) {
		StringBuffer buff=new StringBuffer("");
		
		for(int i=0; i<a.length; i++) {
			if (i==0) {
				buff.append(a[i]);
			} else {
				buff.append(", "+a[i]);
			}
		}
		System.out.println(buff.toString());
	}
	
	private static class ReverseOrder implements Comparator<String> {

		@Override
		public int compare(String o1, String o2) {
			return o2.compareTo(o1);
		}


		
	}
}