Cross-Package Variable Manipulation

Can someone tell me what I'm doing wrong? Basically I'm just trying to add an EntityID into a HashSet so I can track it to set off an explosion when certain parameters are met when it was initially fired.

This is from my main class:

Code:java

public class Core extends JavaPlugin implements Listener
{
private ExplosiveTip explosiveTip = new ExplosiveTip();
private Functions funct = new Functions(this);
 
public void onEnable()
    {
    getCommand("admin").setExecutor(new AdminCommands(this));
    getServer().getPluginManager().registerEvents(this, this);
    getServer().getPluginManager().registerEvents(new ExplosiveTip(), this);
    getLogger().info(getName() + " Has Been Enabled! v" + getDescription().getVersion());
    }
 
public void onDisable()
    {
    getLogger().info(getName() + " Has Been Disabled! v" + getDescription().getVersion());
    }
 
//            CORE EVENTS - REDIRECTION CLASSES            \\
 
@EventHandler
public void projectileLaunch(ProjectileLaunchEvent event)
    {
 
    if(event.getEntity().getShooter() instanceof Player)
        {
        Player player = (Player) event.getEntity().getShooter();
 
        for(ItemStack item : player.getInventory().getContents())
            {
 
            if(item != null && item.hasItemMeta() && item.getItemMeta().hasDisplayName())
                {
                System.out.print(event.getEntity().getEntityId()); //DEBUGGING PURPOSES
                if(item.getItemMeta().getDisplayName().contains("Explosive Tip") && funct.manaManipulation(player, -20))
                    explosiveTip.explosive.add(event.getEntity().getEntityId());
                }
 
            }
 
        }
 
    }
 
}

This is from the class the last line is trying to contact with. If it helps, its' in a different package:

Code:java

public class ExplosiveTip implements Listener
{
public HashSet<Integer> explosive = new HashSet<Integer>();
 
@EventHandler
public void explosiveHit(ProjectileHitEvent event)
    {
    System.out.print(event.getEntity().getEntityId()); //DEBUGGING PURPOSES
 
    if(explosive.contains(event.getEntity().getEntityId()))
        {
        event.getEntity().getWorld().createExplosion(event.getEntity().getLocation(), (float)event.getEntity().getVelocity().length());
        System.out.print(event.getEntity().getVelocity().length()); //DEBUGGING PURPOSES
        explosive.remove(event.getEntity().getEntityId());
        }
 
    }
 
}

I've ruled out that the EntityIDs are different, but when I tried doing for(int numbers : explosive) in the second set of code it came up with nothing, so I'm sure my problem is that it's not adding the number into the HashSet, but I've also ruled out that it isn't getting into that part because I was able to do other sets of code within that if statement parameter. So I'm sure my command for adding it in is wrong, but I don't know why.