TimestampSet implements TimeSet<Double> { @Override public boolean isEmpty() { return size == 0; } TimestampSet();  TimestampSet(int capacity);  TimestampSet(double[] arr); @Override boolean add(Double timestamp); @Override boolean remove(Double timestamp); @Override int size(); @Override boolean isEmpty(); @Override boolean contains(Double timestamp); @Override Double[] toArray(); @Override double[] toPrimitiveArray(); @Override void clear(); @Override int hashCode(); @Override boolean equals(Object obj); String toString(TimeFormat timeFormat, DateTimeZone timeZone); String toString(TimeFormat timeFormat); @Override String toString();  }
@Test public void testEmpty() { TimestampSet set = new TimestampSet(); Assert.assertTrue(set.isEmpty()); }