A method find computer program product for debugging a virtual machine, preferably a target lava virtual machine, without need for the virtual machine to comprise debug information required by a debugger, the method being applied during communication of request packets between the debugger and the virtual machine during execution of the debugger, the method comprising the steps of receiving the request packets from the debugger prior to communication of the request packets to the virtual machine, processing the request packets whereby the required debug information is provided to predetermined packets thereof, transmitting the processed request packets for communication to the virtual machine, receiving reply packets from the virtual machine, processing the reply packets for reply to the debugger, and transmitting the processed reply packets to the debugger. The method and computer program product may also be provided wherein the debug information comprises line tables and the step of processing request packets comprises translating line-based request packets to instruction-based request packets. The method and computer program product may also be provided wherein the formal of the request packets is defined by the Java Debug Wire Protocol (JDWP) or the predetermined request packets may be those packets determined to require debug information in the proxy.