Mob Spawning

What is the code so when hostile mobs try to spawn it replaces all of them with zombies?

I've tried this and it just spams errors:

Code:java

package me.zombie;
 
import org.bukkit.entity.EntityType;
import org.bukkit.entity.Monster;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.Listener;
import org.bukkit.event.entity.CreatureSpawnEvent;
import org.bukkit.plugin.PluginManager;
import org.bukkit.plugin.java.JavaPlugin;
 
public class zombie extends JavaPlugin implements Listener{
 
public void onEnable() {
PluginManager pm = getServer().getPluginManager();
pm.registerEvents(this, this);
 
 
}
 
public void onDisable() {
 
}
@EventHandler (priority = EventPriority.NORMAL)
public void onCreatureSpawn(CreatureSpawnEvent e)
{
 
if (e.getEntity() instanceof Monster)
{
e.getLocation().getWorld().spawnEntity(e.getLocation(), EntityType.ZOMBIE);
e.getEntity().remove();
 
return;
}
}
}
 

 

Code:

@EventHandler(priority = EventPriority.HIGH)
public void onCreatureSpawnEvent(CreatureSpawnEvent event){
World w2 = event.getEntity().getWorld();
w2.setMonsterSpawnLimit(350);
EntityType type = event.getEntity().getType();
if(type == EntityType.CAVE_SPIDER ||
type == EntityType.ZOMBIE ||
type == EntityType.SKELETON ||
type == EntityType.SPIDER ||
type == EntityType.GIANT ||
type == EntityType.SILVERFISH){
Location loc = event.getEntity().getLocation();
event.getEntity().remove();
World w = loc.getWorld();
w.spawnEntity(loc, EntityType.CREEPER);
}
}
}

you can edit that for your own purpose ^^
this replaces all hostile mobs by creepers

 

That just stops them i want were they should spawn to be replaced with zombies

 

i edit it

 

???

 

Code:

@EventHandler(priority = EventPriority.HIGH)
public void onCreatureSpawnEvent(CreatureSpawnEvent event){
World w2 = event.getEntity().getWorld();
w2.setMonsterSpawnLimit(350);
EntityType type = event.getEntity().getType();
if(type == EntityType.CAVE_SPIDER ||
type == EntityType.ZOMBIE ||
type == EntityType.SKELETON ||
type == EntityType.SPIDER ||
type == EntityType.GIANT ||
type == EntityType.SILVERFISH){
Location loc = event.getEntity().getLocation();
event.getEntity().remove();
World w = loc.getWorld();
w.spawnEntity(loc, EntityType.CREEPER);
}
}
}