After a few minutes of running, the server slows down and eventually crashes, I tried deleting all of the plug ins and it still would crash.

Crash Log (Whole log attached):

[19:13:25] [Spigot Watchdog Thread/ERROR]: The server has stopped responding!
[19:13:25] [Spigot Watchdog Thread/ERROR]: Please report this to http://www.spigotmc.org/
[19:13:25] [Spigot Watchdog Thread/ERROR]: Be sure to include ALL relevant console errors and Minecraft crash reports
[19:13:25] [Spigot Watchdog Thread/ERROR]: Spigot version: git-Spigot-db6de12-18fbb24 (MC: 1.8.8)
[19:13:25] [Spigot Watchdog Thread/ERROR]: ------------------------------
[19:13:25] [Spigot Watchdog Thread/ERROR]: Server thread dump (Look for plugins here before reporting to Spigot!):
[19:13:25] [Spigot Watchdog Thread/ERROR]: ------------------------------
[19:13:25] [Spigot Watchdog Thread/ERROR]: Current Thread: Server thread
[19:13:25] [Spigot Watchdog Thread/ERROR]: PID: 16 | Suspended: false | Native: false | State: RUNNABLE
[19:13:25] [Spigot Watchdog Thread/ERROR]: Stack:
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.ArrayList.indexOf(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.ArrayList.contains(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.ArrayList.batchRemove(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.ArrayList.removeAll(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: net.minecraft.server.v1_8_R3.World.tickEntities(World.java:1379)
[19:13:25] [Spigot Watchdog Thread/ERROR]: net.minecraft.server.v1_8_R3.WorldServer.tickEntities(WorldServer.java:597)
[19:13:25] [Spigot Watchdog Thread/ERROR]: net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:786)
[19:13:25] [Spigot Watchdog Thread/ERROR]: net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374)
[19:13:25] [Spigot Watchdog Thread/ERROR]: net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654)
[19:13:25] [Spigot Watchdog Thread/ERROR]: net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.lang.Thread.run(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: ------------------------------
[19:13:25] [Spigot Watchdog Thread/ERROR]: Entire Thread Dump:
[19:13:25] [Spigot Watchdog Thread/ERROR]: ------------------------------
[19:13:25] [Spigot Watchdog Thread/ERROR]: Current Thread: pool-6-thread-1
[19:13:25] [Spigot Watchdog Thread/ERROR]: PID: 51 | Suspended: false | Native: false | State: WAITING
[19:13:25] [Spigot Watchdog Thread/ERROR]: Stack:
[19:13:25] [Spigot Watchdog Thread/ERROR]: sun.misc.Unsafe.park(Native Method)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.concurrent.locks.LockSupport.park(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.concurrent.LinkedBlockingQueue.take(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.concurrent.ThreadPoolExecutor.getTask(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.lang.Thread.run(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: ------------------------------
[19:13:25] [Spigot Watchdog Thread/ERROR]: Current Thread: Chunk I/O Executor Thread-1
[19:13:25] [Spigot Watchdog Thread/ERROR]: PID: 48 | Suspended: false | Native: false | State: WAITING
[19:13:25] [Spigot Watchdog Thread/ERROR]: Stack:
[19:13:25] [Spigot Watchdog Thread/ERROR]: sun.misc.Unsafe.park(Native Method)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.concurrent.locks.LockSupport.park(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.concurrent.LinkedBlockingQueue.take(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.concurrent.ThreadPoolExecutor.getTask(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: java.lang.Thread.run(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: ------------------------------
[19:13:25] [Spigot Watchdog Thread/ERROR]: Current Thread: Netty Server IO #3
[19:13:25] [Spigot Watchdog Thread/ERROR]: PID: 28 | Suspended: false | Native: false | State: RUNNABLE
[19:13:25] [Spigot Watchdog Thread/ERROR]: Thread is waiting on monitor(s):
[19:13:25] [Spigot Watchdog Thread/ERROR]: Locked on:sun.nio.ch.SelectorImpl.lockAndDoSelect(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: Locked on:sun.nio.ch.SelectorImpl.lockAndDoSelect(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: Locked on:sun.nio.ch.SelectorImpl.lockAndDoSelect(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: Stack:
[19:13:25] [Spigot Watchdog Thread/ERROR]: sun.nio.ch.WindowsSelectorImpl$SubSelector.poll0(Native Method)
[19:13:25] [Spigot Watchdog Thread/ERROR]: sun.nio.ch.WindowsSelectorImpl$SubSelector.poll(Unknown Source)
[19:13:25] [Spigot Watchdog Thread/ERROR]: sun.nio.ch.WindowsSelectorImpl$S