public class DriverManager {
    // List of registered JDBC drivers
    private final static CopyOnWriteArrayList<DriverInfo> registeredDrivers = new CopyOnWriteArrayList<>();
    // 该变量被声明为 static, 导致其他类型的数据源设置了 DriverManager 中的该变量后，Hive JDBC 将会使用到其他类型数据源设置的超时时间
    private static volatile int loginTimeout = 0;
    private static volatile java.io.PrintWriter logWriter = null;
    private static volatile java.io.PrintStream logStream = null;
    // Used in println() to synchronize logWriter
    private final static  Object logSync = new Object();

    /* Prevent the DriverManager class from being instantiated. */
    private DriverManager(){}

    /**
     * Sets the maximum time in seconds that a driver will wait
     * while attempting to connect to a database once the driver has
     * been identified.
     *
     * @param seconds the login time limit in seconds; zero means there is no limit
     * @see #getLoginTimeout
     */
    public static void setLoginTimeout(int seconds) {
        loginTimeout = seconds;
    }

    /**
     * Gets the maximum time in seconds that a driver can wait
     * when attempting to log in to a database.
     *
     * @return the driver login time limit in seconds
     * @see #setLoginTimeout
     */
    public static int getLoginTimeout() {
        return (loginTimeout);
    }

    // ...