import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Set;
public class Main {
public static void main(String[] argv) throws Exception {
Set set = new LinkedHashSet();
// Add some elements
set.add("1");
set.add("2");
set.add("3");
set.add("2");
// List the elements
for (Iterator it = set.iterator(); it.hasNext();) {
Object o = it.next();
}
}
}