----- "Ravi Pawar" <ravifc(a)gmail.com&gt; wrote: The error is not throwed by "dm.undefine". looked at and tried your test program, it throws error message like: libvir: QEMU error : Domain not found: no domain with matching name 'tt2' Definitely, it's throwed by: dm =conn.domainLookupByName("tt2"); I guess you looked up the domain by "UUID" before.. so it came the error message saying "no domain with matching uuid .....". The error doesn't influnce the program running forward. e.g. Domain dm1 = conn.domainDefineXML(dumpxml); dm1.create(); int id; id = dm1.getID(); System.out.println(id); dm1.undefine(); You will get the domain ID.. I'm not familiar with Java, guess you can catch the error and turn it into a warning message with "Expection Handler". correct me if I'm not right.. :-) - Osier