code: @CallerSensitive
      public static synchronized void deregisterDriver(Driver driver)
          throws SQLException {
          if (driver == null) {
              return;
          }
  
          println("DriverManager.deregisterDriver: " + driver);
  
          DriverInfo aDriver = new DriverInfo(driver);
          if(registeredDrivers.contains(aDriver)) {
              if (isDriverAllowed(driver, ClassLoader.getSystemClassLoader())) {
                   registeredDrivers.remove(aDriver);
              } else {
                  // If the caller does not have permission to load the driver then
                  // throw a SecurityException.
                  throw new SecurityException();
              }
          } else {
              println("    couldn't find driver to unload");
          }
      }
docs: Drops a driver from the <code>DriverManager</code>'s list.
  Applets can only deregister drivers from their own classloaders.
  
  @param driver the JDBC Driver to drop
  @exception SQLException if a database access error occurs