I am trying to connect to the virtualbox hypervisor through libvirt java binding. I am on Ubuntu 10.04 and I have installed libvirt-0.85, libvirt-java-0.4.6 and virtualbox-ose-dkms. I have configured libvirt project and its java binding at Eclipse and the default test of the binding runs properly. When I try to run a simple test in java with the connection: conn = new Connect("vbox:///session", false) I get the following exception: "exception caught:org.libvirt. LibvirtException: Failed to start the nwfilter driver: Is the daemon running ?" If I try to do the same thing, but instead of using the java biding I use virsh, it works. I am able to connect and start the virtual machine successfully, although none of the nwfilter commands work in virsh. (The nwfilter-list command shows this error: Failed to list network filters. This function is not supported by the connection driver: virConnectNumOfNWFilters) If I run the same java test using the Test hypervisor connection, things work properly. I don't know if I have to install or configure something else in order to get the nwfilter working or if virtualbox doesn't provide support for it, and if it doesn't provide, how can I get rid of this exception and use virtualbox virtual machine connection through java binding ? My objective is being able to use libvirt library commands in a software (in java) which uses virtualization to run jobs in different machines, but without the connection to the hypervisor I can't do anything. I apologize if this question has been already answered. I have tried hard to get the answers for it looking at forums and also in the discussions of this list, but I couldn't. What am I missing? Thanks! -- Tarciso Braz de Oliveira Filho Graduando em Ciência da Computação LSD - Laboratório de Sistemas Distribuídos UFCG 2011