[Fri, 2. Aug 2019 19:20:26 EDT WARN] Exception in thread "Craft Scheduler Thread - 1353"
[Fri, 2. Aug 2019 19:20:26 EDT WARN] org.apache.commons.lang.UnhandledException: Plugin Place v1.0-SNAPSHOT generated an exception while executing task 41
    at org.bukkit.craftbukkit.v1_7_R4.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:57)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.util.ConcurrentModificationException
    at java.util.HashMap$HashIterator.nextNode(HashMap.java:1442)
    at java.util.HashMap$KeyIterator.next(HashMap.java:1466)
    at java.lang.Iterable.forEach(Iterable.java:74)
    at me.place.Place.lambda$savePlayers$1(Place.java:52)
    at org.bukkit.craftbukkit.v1_7_R4.scheduler.CraftTask.run(CraftTask.java:71)
    at org.bukkit.craftbukkit.v1_7_R4.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:53)
    ... 3 more