public class DemoBukkitPlugin extends JavaPlugin { @Override public void onLoad() { // Shortcut of Via.getManager().getProtocolManager().getProtocol(); Protocol1_9To1_8 proto = ViaAlfajor.getProtocol(Protocol1_9To1_8.class); // Class to start the dirty tricks ProtocolHandle<ClientboundPackets1_8, ServerboundPackets1_9> handle = ProtocolHandle.wrap(protocol); // Inject a PacketRemapper into spawn_mob remappers // It wouldn't override any registered remapper handle.injectClientbound(ClientboundPackets1_8.SPAWN_MOB, remapper -> { // Do whatever you want here }); // Inject a remapper for serverbound packets handle.injectServerbound(ServerboundPackets1_9.VEHICLE_MOVE, remapper -> { //... } ); // Inject a remapper overriding all the spawn_mob remappers. handle.injectOverrideClientbound(ClientboundPackets1_8.SPAWN_MOB, remapper -> { // ... }); } }