Unhandled exception type Exception?

Question

I am trying to create a plugin that takes the essentials command /item and gives a lore to every one of the items.

The code I am putting does not have the lore part yet, right now I am just focusing on rewriting the /item command so I can edit it.

public class main extends JavaPlugin implements Listener {
    public static Bukkit plugin;

    @Override
    public void onEnable()
    {
        Bukkit.getServer().getPluginManager().registerEvents(this, this);

        Bukkit.getConsoleSender().sendMessage(ChatColor.DARK_RED + "Enabled!");
    }

    @Override
    public void onDisable()
    {
        getLogger();
        Bukkit.getConsoleSender().sendMessage(ChatColor.DARK_RED + "Disabled!");
    }
    @Override
    public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args) {
        if (cmd.getName().equalsIgnoreCase("item")) { 

            Player user = (Player)sender;
            if (args.length < 1)
            {
                user.sendMessage("Not enough arguments");
            }
            Essentials essentials = (Essentials)getServer().getPluginManager().getPlugin("Essentials");

              IItemDb itemDB = essentials.getItemDb();
              ItemStack stack = essentials.getItemDb().get(args[0]);


            final String itemname = stack.getType().toString().toLowerCase(Locale.ENGLISH).replace("_", "");
            try
            {
                if (args.length > 1 && Integer.parseInt(args[1]) > 0)
                {
                    stack.setAmount(Integer.parseInt(args[1]));
                }
                }
            catch (NumberFormatException e)
            {
                user.sendMessage("Not enough arguements");
            }
            if (args.length > 2)
            {
                MetaItemStack metaStack = new MetaItemStack(stack);
                final boolean allowUnsafe = user.hasPermission("essentials.enchantments.allowunsafe");

                stack = metaStack.getItemStack();
            }


            if (stack.getType() == Material.AIR)
            {
                user.sendMessage("Can not spawn air");
            }

            final String displayName = stack.getType().toString().toLowerCase(Locale.ENGLISH).replace('_', ' ');
            user.sendMessage("Given " + stack.getAmount() + " " + displayName);
            if (user.hasPermission("essentials.oversizedstacks"))
            {
                InventoryWorkaround.addOversizedItems(user.getInventory(), 111, stack);
            }
            else
            { 
                InventoryWorkaround.addItems(user.getInventory(), stack);
            }
            user.updateInventory();
            return true;
        }
            return false; 
    }
}

On this line:

ItemStack stack = essentials.getItemDb().get(args[0]);

I get the error:

Unhandled exception type Exception.

I can fix this by rearranging the bottom closing braces, but then I get errors in the bottom closing braces. Does anyone know what is going on?

Yes, anybody who has the slightest knowledge of Java knows what's going on. Please read through [the official Java tutorial on Exceptions](http://docs.oracle.com/javase/tutorial/essential/exceptions/). Please also note that SO is not a site for teaching beginners how to code, but a site for professional and enthusiast programmers - we expect you to know the basics, and there are plenty of resources to learn them. Do your own research before asking further questions, and only ask on SO as a last resort once you're certain you've stumbled on a problem that's not heavily documented already. — l4mpi, Feb 16 '15 at 14:54

score 0 · Answer 1 · answered Feb 16 '15 at 14:46

This is because IItemDb.get(String) throws a checked exception, which you did not handle. Checked exceptions must be handled, or a compile-time error will be thrown. From §11.2:

The Java programming language requires that a program contains handlers for checked exceptions which can result from execution of a method or constructor. For each checked exception which is a possible result, the throws clause for the method or constructor must mention the class of that exception or one of the superclasses of the class of that exception.

_{(emphasis mine)}

Therefore, you must extend your method signature:

public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args) throws Exception

score 0 · Answer 2 · edited May 23 '17 at 11:53

0

The line ItemStack stack = essentials.getItemDb().get(args[0]); can throw an Exception.

To handle it (and it's mandatory), you have to surround this line with a try/catch block.

try {
    ItemStack stack = essentials.getItemDb().get(args[0]); 
} catch(Exception e) {
    e.printStackTrace();
}

Also, you may want to read this: Why not catch general Exceptions

edited May 23 '17 at 11:53

Community

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answered Feb 16 '15 at 14:48

lmo

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Unhandled exception type Exception?

2 Answers2