TomP2P 5 Beta 8 just released. Check out the latest beta version.
P2P Challenge Task 2015 release
Testing may not succeed all the time due to timing issues. Hole punching is currently being merged, its not working at the moment. Both issues will be resolved.
<dependency>
<groupId>net.tomp2p</groupId>
<artifactId>tomp2p-{module}</artifactId>
<version>5.0-Beta8</version>
</dependency>