### Question:
DatastoreEmulator extends Datastore { @Deprecated public synchronized void start(String emulatorDir, String projectId, String... commandLineOptions) throws DatastoreEmulatorException { checkNotNull(emulatorDir, "emulatorDir cannot be null"); checkNotNull(projectId, "projectId cannot be null"); checkState(state == State.NEW, "Cannot call start() more than once."); try { startEmulatorInternal( emulatorDir + "/cloud_datastore_emulator", projectId, Arrays.asList(commandLineOptions)); state = State.STARTED; } finally { if (state != State.STARTED) { state = State.STOPPED; } } } DatastoreEmulator(RemoteRpc rpc, String localHost, DatastoreEmulatorOptions options); void clear(); @Deprecated synchronized void start(String emulatorDir, String projectId, String... commandLineOptions); synchronized void start(); synchronized void stop(); synchronized File getProjectDirectory();  }### Answer:
@Test public void testArgs() throws DatastoreEmulatorException { DatastoreEmulator datastore = new DatastoreEmulator(null, "blar", options) { @Override void startEmulatorInternal( String emulatorDir, String projectId, List<String> cmdLineOpts) { } }; try { datastore.start(null, "projectId"); fail("expected exception"); } catch (NullPointerException npe) { } try { datastore.start("path/to/emulator", null); fail("expected exception"); } catch (NullPointerException npe) { } datastore.start("path/to/emulator", "projectId"); }