Fixed in 0.7.4 release

You may see a warning in your console about illegal reflective access:

WARNING: Illegal reflective access by space.arim.libertybans.bootstrap.LibertyBansLauncher (file:plugins/LibertyBans_0.2.0-SNAPSHOT.jar) to method java.net.URLClassLoader.addURL(java.net.URL)

Don't worry, in this case it is harmless. The important thing to note is method java.net.URLClassLoader.addURL(java.net.URL). That's a protected method which is not going anywhere.

Sometimes illegal reflective access is bad. If you find a similar warning about a different method or field, e.g. field sun.nio.ch.FileChannelImpl.fd - that may be a problem you should investigate.

Why does this occur?

Your platform (Bukkit or Bungee) does not support adding to the classpath at runtime, so LibertyBans needs to kind of hack this in.

On Velocity, this problem does not happen because Velocity has proper support.