mirror.initJdwpRequest();
try {
JdwpReplyPacket replyPacket = mirror
.requestVM(JdwpCommandPacket.VM_ID_SIZES);
mirror.defaultReplyErrorHandler(replyPacket.errorCode());
DataInputStream replyData = replyPacket.dataInStream();
fFieldIDSize = mirror.readInt("field ID size", replyData); //$NON-NLS-1$
fMethodIDSize = mirror.readInt("method ID size", replyData); //$NON-NLS-1$
fObjectIDSize = mirror.readInt("object ID size", replyData); //$NON-NLS-1$
fReferenceTypeIDSize = mirror.readInt("refType ID size", replyData); //$NON-NLS-1$