tomcat and sqlite

[Saleem Haseeb]

Hi,
I am trying to use sqlite in a web application on tomcat version 8.0.41
The driver that I use to connect to sqlite from within the web application is

<dependency>
  <groupId>org.xerial</groupId>
  <artifactId>sqlite-jdbc</artifactId>
  <version>3.23.1</version>
</dependency>

I am using Linux to deploy the application and whenever there is a connection 
first made to the database I get the driver .so files created as below:

sqlite-3.23.1-71f96c59-5318-4b40-8505-8000876a12e7-libsqlitejdbc.so
sqlite-3.23.1-71f96c59-5318-4b40-8505-8000876a12e7-libsqlitejdbc.so.lck

in the contextDestroyed() hook I am trying to do something as following to 
deregister the driver on my classloader for the webapp like


private void deregisterDrivers() {
    Enumeration<Driver> drivers = DriverManager.getDrivers();
    ClassLoader cl = Thread.currentThread().getContextClassLoader();
    while (drivers.hasMoreElements()) {
        Driver driver = drivers.nextElement();
        if (driver.getClass().getClassLoader() == cl) {
            try {
                logger.info("Deregistering jdbc driver: {}", driver);
                DriverManager.deregisterDriver(driver);
            } catch (SQLException e) {
                logger.info("Error deregistering driver {} due to {}", driver, 
e);
            }
        }
    }
}

the above as pointed out in some questions at stackoverflow says is 
implementation dependent, so I verified and found out that it does not delete 
those so and lck files.

As a workaround, I then tried in the same contextDestroyed method, to delete 
the .so and .so.lck files but then that creates files with the pattern 
.nfsyyyyyyy on my disk. These files seem like the driver files and for some 
reason, if I try to delete those as part of clean up, I get the message "Device 
is Busy" and the .nfs* files hang on the disk and also don't get removed by the 
OS.

I am struggling here to get rid of the drivers gracefully on application 
undeployment. Any help is appreciated!

Regards,
Haseeb