The Bukkit API allows a programmer to do more than just cancel an event. Depending on the event, you can modify many of its aspects. In this next project, we will modify zombies as they spawn. Every time a zombie spawns, we will give it 40 health rather than the default 20. This will make zombies more difficult to kill.
Create a new project as you would for any plugin. We will call this plugin MobEnhancer. Similar to what we did with the NoRain plugin, have the main class implement Listener and add the following line of code to the onEnable method to register the EventHandlers method:
getServer().getPluginManager().registerEvents(this, this);
For this project, we will have an EventHandler method that listens for mobs spawning. This will be the CreatureSpawnEvent class. This event has many methods that we can call to either modify the event or gain more information about it. We only wish to modify zombies that are spawned. Therefore, the first thing that we will...