import java.util.*; class Demo { public static void main (String[] args) { int setSize = 10000000; long start, end; long elapsed = 0; Set set = new HashSet(); // Set set = new TreeSet(); start = System.currentTimeMillis(); System.out.println("add " + setSize); for (int i = 0; i < setSize; i++) set.add(new Integer(i)); end = System.currentTimeMillis(); elapsed = end - start; System.out.println("time: " + elapsed); start = System.currentTimeMillis(); System.out.println("contains " + setSize); for (int i = 0; i < setSize; i++) set.contains(new Integer(i)); end = System.currentTimeMillis(); elapsed = end - start; System.out.println("time: " + elapsed); start = System.currentTimeMillis(); System.out.println("remove " + setSize); for (int i = 0; i < setSize; i++) set.remove(new Integer(i)); end = System.currentTimeMillis(); elapsed = end - start; System.out.println("time: " + elapsed); } }