Solved A wild java.lang.ClassCastException appeared...

Hi,

I'm making a minigame, but I have a problem... A java.lang.ClassCastException appears on Line 32 in my Sign manager. And yes, I extended JavaPlugin in my Main class!

Error:

Code:

[20:28:15 ERROR]: Error occurred while enabling Titanfall v0.6-ALPHA_BUILD (Is i
t up to date?)
java.lang.ClassCastException: org.bukkit.craftbukkit.v1_7_R3.block.CraftBlockSta
te cannot be cast to org.bukkit.block.Sign
        at ph.url.techzone.Titanfall.SignManager.<init>(SignManager.java:32) ~[?
:?]
        at ph.url.techzone.Titanfall.Main.onEnable(Main.java:47) ~[?:?]

SignManager Line 32:

Code:java

Sign s = (Sign) loc.getBlock().getState();

onEnable line 47:

Code:java

pm.registerEvents(new SignManager(), this);
 
//pm variable
PluginManager pm = Bukkit.getServer().getPluginManager();

Full SignManager class:

Code:java

package ph.url.techzone.Titanfall;
 
import java.util.ArrayList;
import java.util.HashMap;
 
import org.bukkit.ChatColor;
import org.bukkit.Location;
import org.bukkit.block.Sign;
import org.bukkit.configuration.ConfigurationSection;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.block.Action;
import org.bukkit.event.block.SignChangeEvent;
import org.bukkit.event.player.PlayerInteractEvent;
 
import ph.url.techzone.Titanfall.Arena.ArenaState;
 
public class SignManager implements Listener {
 
    private static HashMap<Sign, Integer> signs = new HashMap<Sign, Integer>();
 
    public SignManager() {
 
        if (!SettingsManager.getLobbySigns().contains("signs")) {
            SettingsManager.getLobbySigns().createConfigurationSection("signs");
        }
 
        for (String str : SettingsManager.getLobbySigns().<ConfigurationSection>get("signs").getKeys(true)) {
            ConfigurationSection section = SettingsManager.getLobbySigns().get("signs." + str);
 
            Location loc = LocationUtil.locationFromConfig(section.getConfigurationSection("location"), false);
            Sign s = (Sign) loc.getBlock().getState();
 
            signs.put(s, section.getInt("arenaNumber"));
        }
    }
 
    public static ArrayList<Sign> getSigns(Arena a) {
        ArrayList<Sign> s = new ArrayList<Sign>();
 
        for (Sign sign : signs.keySet()) {
            if (ArenaManager.getInstance().getArena(signs.get(sign)) == a) s.add(sign);
        }
 
        return s;
    }
 
 
    @EventHandler
    public void onSignChange(SignChangeEvent e) {
        if (e.getLine(0).equalsIgnoreCase("[Titanfall]")) {
            int id;
            try { id = Integer.parseInt(e.getLine(1)); }
            catch (Exception ex) { e.getPlayer().sendMessage(Main.pre + ChatColor.RED + "That is not a valid arena number!"); return; }
 
            Arena a = ArenaManager.getInstance().getArena(id);
            if (a == null) {
                e.getPlayer().sendMessage(Main.pre + "That is not a valid arena!");
                return;
            }
 
            ConfigurationSection section = SettingsManager.getLobbySigns().createConfigurationSection("signs." + SettingsManager.getLobbySigns().<ConfigurationSection>get("signs").getKeys(true).size() + 1);
 
            ConfigurationSection location = section.createSection("location");
            location.set("world", e.getBlock().getLocation().getWorld().getName());
            location.set("x", e.getBlock().getLocation().getX());
            location.set("y", e.getBlock().getLocation().getY());
            location.set("z", e.getBlock().getLocation().getZ());
 
            section.set("arenaNumber", id);
 
            signs.put((Sign) e.getBlock().getState(), a.getID());
 
            e.setLine(0, ChatColor.LIGHT_PURPLE + "Titanfall");
            e.setLine(2,  a.getCurrentPlayers() + "/" + SettingsManager.getArenas().get("arenas." + id + ".numPlayers") + " Players");
 
            if (a.getState().equals(ArenaState.DISABLED)) {
                e.setLine(3, ChatColor.DARK_RED + "Disabled");
            }
            else if (a.getState().equals(ArenaState.WAITING)) {
                e.setLine(3,ChatColor.GREEN + "Waiting");
            }
            else if (a.getState().equals(ArenaState.COUNTING_DOWN)) {
                e.setLine(3, ChatColor.RED + "" + ChatColor.UNDERLINE + "Counting Down");
            }
            else if (a.getState().equals(ArenaState.STARTED)){
                e.setLine(3, ChatColor.DARK_AQUA + "Started");
            }
            else {
                e.setLine(3, ChatColor.RED + "Error");
            }
        }
    }
 
    @EventHandler
    public void onPlayerInteract(PlayerInteractEvent e) {
        if (!(e.getAction() == Action.RIGHT_CLICK_AIR) && !(e.getAction() == Action.RIGHT_CLICK_BLOCK)) return;
 
        if (e.getClickedBlock() == null || e.getClickedBlock().getState() == null) return;
 
        if (e.getClickedBlock().getState() instanceof Sign) {
            Sign s = (Sign) e.getClickedBlock().getState();
            if (s.getLine(0).equalsIgnoreCase(ChatColor.LIGHT_PURPLE + "Titanfall")) {
                ArenaManager.getInstance().getArena(Integer.parseInt(s.getLine(1))).addPlayer(e.getPlayer());
            }
        }
    }
}

Thanks in advance,

Bram

 

You should check that it actually is a sign first, and that the block state is an instanceof Sign.

 

It seems you never checked if it was actually a sign before you started calling it a sign.

 

bramhaag Your block is not a sign! Add a check if it is a sign before casting the block state.

Edit: This forum should really notify you when someone else wrote an answer before you

 

_LB Gamecube762 Zettelkasten
Do you guys mean to check if it is a sign by using the saved location?

_LB Ninja'd you all

 

bramhaag Use the location to get the block, then check if the block's state is an instanceof a Sign

 

Code:

if(block instanceof Sign){
//now cast to sign
}

 

Gamecube762
That was what I tried to explain I will try it and post the results in a minute

Double0negative
Thanks for the code snippet

Zettelkasten Double0negative _LB

Still getting the same error, but now on an other line

Code:java

if(loc.getBlock() instanceof Sign) {//Getting the error on this line
Sign s = (Sign) loc.getBlock().getState();
 
signs.put(s, section.getInt("arenaNumber"));
}

EDIT: nevermind, it is a NPE

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

bramhaag Your signs map is null.

 

Zettelkasten You're right. So, how to fix it . I don't get it... How can a map be null?

 

bramhaag Actually, are you sure the map is null? You do initialize it in line 20!
Which line does the NPE occur?

 

Zettelkasten Double0negative Gamecube762
Well, I did some research about the HashMap being null, but that I looked to the error that was generated. So, the hashmap wasn't null.

The error:

Code:

[21:18:47 ERROR]: Error occurred while enabling Titanfall v0.6-ALPHA_BUILD (Is
t up to date?)
java.lang.ClassCastException: java.lang.String cannot be cast to org.bukkit.co
iguration.ConfigurationSection
        at ph.url.techzone.Titanfall.SignManager.<init>(SignManager.java:29) ~
:?]
        at ph.url.techzone.Titanfall.Main.onEnable(Main.java:47) ~[?:?]

The code:

Code:java

for (String str : SettingsManager.getLobbySigns().<ConfigurationSection>get("signs").getKeys(true)) {
ConfigurationSection section = SettingsManager.getLobbySigns().get("signs." + str);// Line 29
 
Location loc = LocationUtil.locationFromConfig(section.getConfigurationSection("location"), false);
if(loc != null && loc.getBlock() instanceof Sign) {
Sign s = (Sign) loc.getBlock().getState();
 
signs.put(s, section.getInt("arenaNumber"));
}

Nobody?

 

bramhaag
SettingsManager.getLobbySigns().get("signs." + str) returns a ConfigurationSection, not a String. I would need the SettingsManager to find out the exact problem though.

 

The whole class is kinda big, so here you have a snippet

Code:java

    public ConfigurationSection createConfigurationSection(String path) {
        ConfigurationSection cs = config.createSection(path);
        try { config.save(file); }
        catch (Exception e) { e.printStackTrace(); }
        return cs;
    }

 

bramhaag The "getLobbySigns()" method is the interesting one

 

Here

Code:java

    public static SettingsManager getLobbySigns() {
        return lobbySigns;
    }

So, i don't think that you can do a shit with this, here you have the lobbySigns variable

Code:java

    private static SettingsManager lobbySigns = new SettingsManager("lobbysigns");

And now you probaly want the SettingsManager method constructor thingie

Code:java

private SettingsManager(String fileName) {
        System.out.println(Main.getPlugin());
 
        if (!Main.getPlugin().getDataFolder().exists()) {
            Main.getPlugin().getDataFolder().mkdir();
        }
 
        file = new File(Main.getPlugin().getDataFolder(), fileName + ".yml");
 
 
        if (!file.exists()) {
            try {
                file.createNewFile();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
 
        config = YamlConfiguration.loadConfiguration(file);
    }

 

bramhaag Can you please post the "lobbysigns.yml" file?
Also, the method SettingsManager.get(String) would be handy.

My guess is that the value in lobbysigns.yml for the key "signs" are no Strings but nested configurations.

 

The lobbysigns.yml file

Code:

signs:
  '01':
    location:
      world: world
      x: 730.0
      y: 42.0
      z: 312.0
    arenaNumber: 1

And the get method

Code:java

@SuppressWarnings("unchecked")
    public <T> T get(String path) {
        return (T) config.get(path);
    }
 
//The config variable
config = YamlConfiguration.loadConfiguration(file);// This gets called in the construction thingie

 

bramhaag Changing line 28 (i believe) to getKeys(false) should fix your problem.
What was happening: If you set it to true, it also returns all nested keys, such as signs.01.location.word. And then, of cause, you will only get a boolean ("world"), and no configuration section.

I will go sleep now, bye bye. Hopefully this solves the problem

 

Zettelkasten Thanks, this was the fix!