Question: I saw that there is a very nice python library ([PyBBIO](https://github.com/alexanderhiam/PyBBIO)) for direct Control of the BBB using mmap on /dev/mem/ (granted not for the muxing). With some goodies like Webmonitor etc. Unfortunatly this library is not running on the 3.8 Kernel.

Are there any viable alternatives in python/c/c++ using mmap? I saw some but non was as complete as the mentioned PyBBIO.

I did successfully try the solution explained [here](https://stackoverflow.com/questions/13124271/driving-beaglebone-gpio-through-dev-mem). But implementing everything (UART/PWM) sounds like it would be something to difficult for me to do...

yours
magu\_

Answer: 
There are 2 main causes for this.

1. A bad/corrupt JAR file in your classpath.
2. The JVM built-in URL caching getting in the way.

For a bad/corrupt JAR file, you'll have to isolate that on your own, figure out which one it is. Maybe by just unjaring all of them one by one till you find the problematic one.

As for the JVM URL caching, this seems to [cause problems with dynamic classloaders like OSGi or hot-deploy scenarios](https://bugs.eclipse.org/bugs/show_bug.cgi?id=364936) the most.

For this scenario, you can tell jetty to set the [`URLConnection.setUseCaches(boolean)`](http://docs.oracle.com/javase/7/docs/api/java/net/URLConnection.html#setUseCaches%28boolean%29) for each URLConnection attempt of its own.

To disable the JVM caches, add the following snippet of XML to your `etc/jetty.xml`

```xml
<Set class="org.eclipse.jetty.util.resource.Resource"
     name="defaultUseCaches">false</Set>

```
I had the same problem after deploying jenkins war; all I had to do was to restart the server after the deploy.
Hope it helps.