Config error

Hey, I have this code:

Code:

public class AddCpEvent implements Listener{
    ArrayList<String> Loclist = (ArrayList<String>) Main.plugin.getConfig().getStringList("CoalMine");

    @EventHandler
    public void onClick(BlockBreakEvent e){
        Player p = e.getPlayer();
        if(Main.editmode.contains(p.getUniqueId())){
            Block b = e.getBlock();
            if(b.getType().equals(Material.GOLD_PLATE)){
                e.setCancelled(true);
                p.sendMessage(Var.pr + ChatColor.GREEN + "New location added!");
            Main.loc.add(b.getLocation().toString());
             Main.plugin.getConfig().set("CheckPoints", Loclist);
             Main.plugin.saveConfig();

            }

And this is my error:

Code:

[17:41:50] [Server thread/ERROR]: Error occurred while enabling NAME v0.0.1 (Is it up to date?)
java.lang.NullPointerException
    at me.jumbo1907.gmcParkour.event.AddCpEvent.<init>(AddCpEvent.java:18) ~[?:?]
    at me.jumbo1907.gmcParkour.main.Main.onEnable(Main.java:24) ~[?:?]
    at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:321) ~[spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:340) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugin(CraftServer.java:356) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at org.bukkit.craftbukkit.v1_8_R3.CraftServer.enablePlugins(CraftServer.java:316) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at org.bukkit.craftbukkit.v1_8_R3.CraftServer.reload(CraftServer.java:742) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at org.bukkit.Bukkit.reload(Bukkit.java:534) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:25) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchCommand(CraftServer.java:642) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at net.minecraft.server.v1_8_R3.PlayerConnection.handleCommand(PlayerConnection.java:1135) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at net.minecraft.server.v1_8_R3.PlayerConnection.a(PlayerConnection.java:970) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(PacketPlayInChat.java:45) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(PacketPlayInChat.java:1) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at net.minecraft.server.v1_8_R3.PlayerConnectionUtils$1.run(SourceFile:13) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_101]
    at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_101]
    at net.minecraft.server.v1_8_R3.SystemUtils.a(SystemUtils.java:19) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:718) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:367) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:657) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:560) [spigot-1.8.7.jar:git-Spigot-d2856ae-8f0f4ed]
    at java.lang.Thread.run(Unknown Source) [?:1.8.0_101]
[17:41:50] [Server thread/INFO]: [WorldEdit] Enabling WorldEdit v6.1;no_git_id

 

@Jumb_1907
Please post the Main class, what is line 24 in main?
And line 18 in AddCpEvent class.

 

Line 24 :
Bukkit.getServer().getPluginManager().registerEvents(new AddCpEvent(), this);
Line 18:
ArrayList<String> Loclist = (ArrayList<String>) Main.plugin.getConfig().getStringList("CoalMine");

 

@Jumb_1907 Your field plugin must be null or the list does not exist in the config or the config is not loaded

 

This list doesn't exist because It's empty in the beginning. How can I add something to an empty list in the config?

 

@Jumb_1907 empty and doesnt exist is not the same.
Create it on the config file. Or in the constructor, check if it's not null before to set it