final ConnectionManager pool = new ConnectionPool();
pool.setMaxConnectionsPerHost(1);
try {
Connection connection = pool.acquire(host);
Assert.assertNotNull(connection);
pool.release(connection);
connection = pool.acquire(host);
Assert.assertNotNull(connection);
ExecutorService service = Executors.newSingleThreadExecutor();
service.invokeAny(Collections.singleton(new Callable<Connection>() {
@Override