[16:08:20 FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
        at java.util.concurrent.FutureTask$Sync.innerGet(Unknown Source) ~[?:1.7.0_09]
        at java.util.concurrent.FutureTask.get(Unknown Source) ~[?:1.7.0_09]
        at net.minecraft.server.v1_9_R1.SystemUtils.a(SourceFile:46) [spigot.jar:git-Spigot-b39373b-73eff0d]
        at net.minecraft.server.v1_9_R1.MinecraftServer.D(MinecraftServer.java:721) [spigot.jar:git-Spigot-b39373b-73eff0d]
        at net.minecraft.server.v1_9_R1.DedicatedServer.D(DedicatedServer.java:400) [spigot.jar:git-Spigot-b39373b-73eff0d]
        at net.minecraft.server.v1_9_R1.MinecraftServer.C(MinecraftServer.java:660) [spigot.jar:git-Spigot-b39373b-73eff0d]
        at net.minecraft.server.v1_9_R1.MinecraftServer.run(MinecraftServer.java:559) [spigot.jar:git-Spigot-b39373b-73eff0d]
        at java.lang.Thread.run(Unknown Source) [?:1.7.0_09]
Caused by: java.lang.NullPointerException
        at net.minecraft.server.v1_9_R1.StructureGenerator.a(StructureGenerator.java:201) ~[spigot.jar:git-Spigot-b39373b-73eff0d]
        at net.minecraft.server.v1_9_R1.WorldGenStronghold.c(SourceFile:96) ~[spigot.jar:git-Spigot-b39373b-73eff0d]
        at net.minecraft.server.v1_9_R1.WorldGenStronghold.getNearestGeneratedFeature(SourceFile:58) ~[spigot.jar:git-Spigot-b39373b-73eff0d]
        at org.bukkit.craftbukkit.v1_9_R1.generator.CustomChunkGenerator.findNearestMapFeature(CustomChunkGenerator.java:225) ~[spigot.jar:git-Spigot-b39373b-73eff0d]
        at net.minecraft.server.v1_9_R1.ChunkProviderServer.a(ChunkProviderServer.java:339) ~[spigot.jar:git-Spigot-b39373b-73eff0d]
        at net.minecraft.server.v1_9_R1.ItemEnderEye.a(SourceFile:82) ~[spigot.jar:git-Spigot-b39373b-73eff0d]
        at net.minecraft.server.v1_9_R1.ItemStack.a(ItemStack.java:236) ~[spigot.jar:git-Spigot-b39373b-73eff0d]
        at net.minecraft.server.v1_9_R1.PlayerInteractManager.a(PlayerInteractManager.java:385) ~[spigot.jar:git-Spigot-b39373b-73eff0d]
        at net.minecraft.server.v1_9_R1.PlayerConnection.a(PlayerConnection.java:922) ~[spigot.jar:git-Spigot-b39373b-73eff0d]
        at net.minecraft.server.v1_9_R1.PacketPlayInBlockPlace.a(PacketPlayInBlockPlace.java:27) ~[spigot.jar:git-Spigot-b39373b-73eff0d]
        at net.minecraft.server.v1_9_R1.PacketPlayInBlockPlace.a(PacketPlayInBlockPlace.java:1) ~[spigot.jar:git-Spigot-b39373b-73eff0d]
        at net.minecraft.server.v1_9_R1.PlayerConnectionUtils$1.run(SourceFile:13) ~[spigot.jar:git-Spigot-b39373b-73eff0d]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.7.0_09]
        at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) ~[?:1.7.0_09]
        at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.7.0_09]
        at net.minecraft.server.v1_9_R1.SystemUtils.a(SourceFile:45) ~[spigot.jar:git-Spigot-b39373b-73eff0d]