Solved Console error! Help :3!

Hey guys! So when I was testing my plugin, I got this error after the players in an arraylist was teleported! Any idea what the error is? I can't understand this kind of error but it does tell what line!

Code:

Code:

ID2 = Bukkit.getScheduler().scheduleSyncRepeatingTask(plugin, new Runnable(){
                                int iii = 1;
                             
                                public void run(){
                                    if (iii > 0){
                                        iii--;
                                    }else{
                                        for (String playername : join){ // This is 386
                                            Player players = getServer().getExactPlayer(playername);
                                            join.remove(players.getName());
                                            Bukkit.getScheduler().cancelTask(ID2);
                                        }
                                    }
                                }
                            }, 0, 20L);

Error:

Code:

[20:52:04 WARN]: [Game] Task #172 for EnderPearlsGame v1 generated an
exception
java.util.ConcurrentModificationException
        at java.util.ArrayList$Itr.checkForComodification(Unknown Source) ~[?:1.
7.0_55]
        at java.util.ArrayList$Itr.next(Unknown Source) ~[?:1.7.0_55]
        at me.jetsinsu.theendersgame.TheEndersGame$1$1$1.run(TheEndersGame.java:
386) ~[?:?]
        at org.bukkit.craftbukkit.v1_7_R1.scheduler.CraftTask.run(CraftTask.java
:53) ~[craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
        at org.bukkit.craftbukkit.v1_7_R1.scheduler.CraftScheduler.mainThreadHea
rtbeat(CraftScheduler.java:345) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks
]
        at net.minecraft.server.v1_7_R1.MinecraftServer.u(MinecraftServer.java:5
87) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
        at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:2
50) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
        at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:5
45) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
        at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java
:457) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
        at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:6
17) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]

 

You can't remove from a list you're using "for () {", use Iterable

Took me 3 days to realize it. Also, use:
new BukkitRunnable() {
// your variables
public void run() {
// your run method
}
}.runTimer(plugin, delay, delay);
it is more efficient than getScheduler().schedule, and you can cancel by doing this.cancelTask()

 

rfsantos1996

Wait a minute, I can do "join.clear();" right?

 

yeah, right, but just to you know, you can iterate if you want just some entries to be removed (;

 

Ok. :3