### Question:
Epoch extends LogicalTimestamp { public static Epoch of(long value) { return new Epoch(value); } Epoch(long value); static Epoch of(long value);  }### Answer:
@Test public void testLogicalTimestamp() throws Exception { Epoch epoch = Epoch.of(1); assertEquals(1, epoch.value()); assertTrue(epoch.isNewerThan(Epoch.of(0))); assertFalse(epoch.isNewerThan(Epoch.of(2))); assertTrue(epoch.isOlderThan(Epoch.of(2))); assertFalse(epoch.isOlderThan(Epoch.of(0))); }