### Question:
MacPidMachineIdProvider implements MachineIdProvider { @Override public long getMachineId() { return machineId; } MacPidMachineIdProvider(); @Override long getMachineId();  }### Answer:
@Test public void validateProvider() { Assert.assertEquals("Machine id's are not deterministic", new MacPidMachineIdProvider().getMachineId(), new MacPidMachineIdProvider().getMachineId()); if(new MacPidMachineIdProvider().getMachineId() == 0L) { System.err.println("Could not detect MAC address"); } }