### Question:
ConnectionManager { public static ConnectionManager getInstance() { return instance; } private  ConnectionManager();   ConnectionManager(DataSourceFactory factory, Ticker ticker, long sleepIntervalNanos); static ConnectionManager getInstance(); Connection getConnection(String server, String jdbcUrl, Properties connectionConfiguration, boolean isPoolEnabled, Properties poolConfiguration, String qualifier); static String maskPassword(String password);  }### Answer:
@Test public void testSingletonInstance() { assertSame(manager, ConnectionManager.getInstance()); }