### Question:
Version implements Timestamp { public Version(long version) { this.version = version; } Version(long version); long value(); @Override int compareTo(Timestamp o); @Override int hashCode(); @Override boolean equals(Object obj); @Override String toString();  }### Answer:
@Test public void testVersion() { Version version1 = new Version(1); Version version2 = new Version(1); assertTrue(version1.equals(version2)); assertTrue(version1.hashCode() == version2.hashCode()); assertTrue(version1.value() == version2.value()); Version version3 = new Version(2); assertFalse(version1.equals(version3)); assertFalse(version1.hashCode() == version3.hashCode()); assertFalse(version1.value() == version3.value()); }