Techniques and systems for modifying a virtual machine functionality. Archive files each including at least a class files are received. The archive files are stored within the virtual machine. The virtual machine runs on a host system and neither the virtual machine nor the host system are restarted in response to the receiving or storing of the archive files. Files of the host system are scanned to find class files that are not included in a class path for the virtual machine. The class files are copied to a class path for the virtual machine. Neither the virtual machine nor the host system are restarted in response to the copying of the class files. The classes corresponding to the class files are registered in the virtual machine in response to the copying of the class files to the class path. Neither the virtual machine nor the host system are restarted in response to the registration of the classes.