Java tutorial
import java.util.HashSet; import java.util.Set; public class FindDupsAndUnique { public static void main(String args[]) { Set uniques = new HashSet(); Set dups = new HashSet(); String[] values = new String[] { "java", "java2", "java2s", "javas", "java" }; for (int i = 0; i < values.length; i++) if (!uniques.add(values[i])) dups.add(values[i]); uniques.removeAll(dups); // Destructive set-difference System.out.println("Unique words: " + uniques); System.out.println("Duplicate words: " + dups); } }