[18:36:12] [Server thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
at java.util.concurrent.FutureTask.report(Unknown Source) ~[?:1.8.0_151]
at java.util.concurrent.FutureTask.get(Unknown Source) ~[?:1.8.0_151]
at net.minecraft.util.Util.func_181617_a(SourceFile:47) [h.class:?]
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:721) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:666) [MinecraftServer.class:?]
at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:239) [chd.class:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:524) [MinecraftServer.class:?]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_151]
Caused by: java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
at org.poly2tri.geometry.polygon.Polygon.(Polygon.java:17) ~[Polygon.class:?]
at org.dimdev.ddutils.lsystem.LSystem.tesselate(LSystem.java:370) ~[LSystem.class:?]
at org.dimdev.ddutils.lsystem.LSystem.generateLSystem(LSystem.java:89) ~[LSystem.class:?]
at org.dimdev.ddutils.lsystem.LSystem.(LSystem.java:31) ~[LSystem.class:?]
at org.dimdev.dimdoors.shared.tileentities.TileEntityFloatingRift.(TileEntityFloatingRift.java:46) ~[TileEntityFloatingRift.class:?]
at org.dimdev.dimdoors.shared.blocks.BlockFloatingRift.createNewTileEntity(BlockFloatingRift.java:43) ~[BlockFloatingRift.class:?]
at org.dimdev.dimdoors.shared.blocks.BlockFloatingRift.func_149915_a(BlockFloatingRift.java:28) ~[BlockFloatingRift.class:?]
at net.minecraft.block.Block.createTileEntity(Block.java:1274) ~[aow.class:?]
at net.minecraft.world.chunk.Chunk.func_177436_a(Chunk.java:623) ~[axw.class:?]
at net.minecraft.world.World.func_180501_a(World.java:342) ~[amu.class:?]
at net.minecraft.world.World.func_175656_a(World.java:424) ~[amu.class:?]
at org.dimdev.dimdoors.shared.items.ItemStabilizedRiftSignature.func_180614_a(ItemStabilizedRiftSignature.java:72) ~[ItemStabilizedRiftSignature.class:?]
at net.minecraftforge.common.ForgeHooks.onPlaceItemIntoWorld(ForgeHooks.java:851) ~[ForgeHooks.class:?]
at net.minecraft.item.ItemStack.func_179546_a(ItemStack.java:186) ~[aip.class:?]
at net.minecraft.server.management.PlayerInteractionManager.func_187251_a(PlayerInteractionManager.java:478) ~[or.class:?]
at net.minecraft.network.NetHandlerPlayServer.func_184337_a(NetHandlerPlayServer.java:739) ~[pa.class:?]
at net.minecraft.network.play.client.CPacketPlayerTryUseItemOnBlock.func_148833_a(SourceFile:55) ~[ma.class:?]
at net.minecraft.network.play.client.CPacketPlayerTryUseItemOnBlock.func_148833_a(SourceFile:11) ~[ma.class:?]
at net.minecraft.network.PacketThreadUtil$1.run(SourceFile:13) ~[hv$1.class:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_151]
at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_151]
at net.minecraft.util.Util.func_181617_a(SourceFile:46) ~[h.class:?]
... 5 more
Caused by: java.lang.ClassNotFoundException: org.slf4j.LoggerFactory
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:101) ~[launchwrapper-1.12.jar:?]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_151]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_151]
at org.poly2tri.geometry.polygon.Polygon.(Polygon.java:17) ~[Polygon.class:?]
at org.dimdev.ddutils.lsystem.LSystem.tesselate(LSystem.java:370) ~[LSystem.class:?]
at org.dimdev.ddutils.lsystem.LSystem.generateLSystem(LSystem.java:89) ~[LSystem.class:?]
at org.dimdev.ddutils.lsystem.LSystem.(LSystem.java:31) ~[LSystem.class:?]
at org.dimdev.dimdoors.shared.tileentities.TileEntityFloatingRift.(TileEntityFloatingRift.java:46) ~[TileEntityFloatingRift.class:?]
at org.dimdev.dimdoors.shared.blocks.BlockFloatingRift.createNewTileEntity(BlockFloatingRift.java:43) ~[BlockFloatingRift.class:?]
at org.dimdev.dimdoors.shared.blocks.BlockFloatingRift.func_149915_a(BlockFloatingRift.java:28) ~[BlockFloatingRift.class:?]
at net.minecraft.block.Block.createTileEntity(Block.java:1274) ~[aow.class:?]
at net.minecraft.world.chunk.Chunk.func_177436_a(Chunk.java:623) ~[axw.class:?]
at net.minecraft.world.World.func_180501_a(World.java:342) ~[amu.class:?]
at net.minecraft.world.World.func_175656_a(World.java:424) ~[amu.class:?]
at org.dimdev.dimdoors.shared.items.ItemStabilizedRiftSignature.func_180614_a(ItemStabilizedRiftSignature.java:72) ~[ItemStabilizedRiftSignature.class:?]
at net.minecraftforge.common.ForgeHooks.onPlaceItemIntoWorld(ForgeHooks.java:851) ~[ForgeHooks.class:?]
at net.minecraft.item.ItemStack.func_179546_a(ItemStack.java:186) ~[aip.class:?]
at net.minecraft.server.management.PlayerInteractionManager.func_187251_a(PlayerInteractionManager.java:478) ~[or.class:?]
at net.minecraft.network.NetHandlerPlayServer.func_184337_a(NetHandlerPlayServer.java:739) ~[pa.class:?]
at net.minecraft.network.play.client.CPacketPlayerTryUseItemOnBlock.func_148833_a(SourceFile:55) ~[ma.class:?]
at net.minecraft.network.play.client.CPacketPlayerTryUseItemOnBlock.func_148833_a(SourceFile:11) ~[ma.class:?]
at net.minecraft.network.PacketThreadUtil$1.run(SourceFile:13) ~[hv$1.class:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_151]
at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_151]
at net.minecraft.util.Util.func_181617_a(SourceFile:46) ~[h.class:?]
... 5 more
[18:36:13] [Server thread/INFO] [OTG]: Pre-generating world "Biome Bundle" chunk X7 Z-10. Radius: 15 Spawned: 438/961 46% done. Elapsed: 00:01:39 ETA: 00:01:59 Mem: 32% 2657 / 8192 MB
[18:36:14] [Server thread/INFO] [OTG]: Pre-generating world "Biome Bundle" chunk X11 Z-10. Radius: 15 Spawned: 442/961 46% done. Elapsed: 00:01:40 ETA: 00:01:58 Mem: 47% 3873 / 8192 MB
[18:36:15] [Server thread/INFO] [OTG]: Pre-generating world "Biome Bundle" chunk X-11 Z-9. Radius: 15 Spawned: 464/961 48% done. Elapsed: 00:01:41 ETA: 00:01:49 Mem: 39% 3275 / 8192 MB
[18:36:16] [Server thread/INFO] [OTG]: Pre-generating world "Biome Bundle" chunk X-11 Z-4. Radius: 15 Spawned: 469/961 49% done. Elapsed: 00:01:42 ETA: 00:01:48 Mem: 32% 2637 / 8192 MB
[18:36:17] [Server thread/INFO] [OTG]: Pre-generating world "Biome Bundle" chunk X-11 Z-1. Radius: 15 Spawned: 472/961 49% done. Elapsed: 00:01:44 ETA: 00:01:48 Mem: 43% 3543 / 8192 MB
[18:36:18] [Server thread/INFO] [OTG]: Pre-generating world "Biome Bundle" chunk X-8 Z-11. Radius: 15 Spawned: 510/961 53% done. Elapsed: 00:01:45 ETA: 00:01:33 Mem: 28% 2349 / 8192 MB
[18:36:19] [Server thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NoClassDefFoundError: Could not initialize class org.dimdev.ddutils.lsystem.LSystem
at java.util.concurrent.FutureTask.report(Unknown Source) ~[?:1.8.0_151]
at java.util.concurrent.FutureTask.get(Unknown Source) ~[?:1.8.0_151]
at net.minecraft.util.Util.func_181617_a(SourceFile:47) [h.class:?]
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:721) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:666) [MinecraftServer.class:?]
at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:239) [chd.class:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:524) [MinecraftServer.class:?]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_151]
Caused by: java.lang.NoClassDefFoundError: Could not initialize class org.dimdev.ddutils.lsystem.LSystem
at org.dimdev.dimdoors.shared.tileentities.TileEntityFloatingRift.(TileEntityFloatingRift.java:46) ~[TileEntityFloatingRift.class:?]
at org.dimdev.dimdoors.shared.blocks.BlockFloatingRift.createNewTileEntity(BlockFloatingRift.java:43) ~[BlockFloatingRift.class:?]
at org.dimdev.dimdoors.shared.blocks.BlockFloatingRift.func_149915_a(BlockFloatingRift.java:28) ~[BlockFloatingRift.class:?]
at net.minecraft.block.Block.createTileEntity(Block.java:1274) ~[aow.class:?]
at net.minecraft.world.chunk.Chunk.func_177436_a(Chunk.java:623) ~[axw.class:?]
at net.minecraft.world.World.func_180501_a(World.java:342) ~[amu.class:?]
at net.minecraft.world.World.func_175656_a(World.java:424) ~[amu.class:?]
at org.dimdev.dimdoors.shared.items.ItemStabilizedRiftSignature.func_180614_a(ItemStabilizedRiftSignature.java:79) ~[ItemStabilizedRiftSignature.class:?]
at net.minecraftforge.common.ForgeHooks.onPlaceItemIntoWorld(ForgeHooks.java:851) ~[ForgeHooks.class:?]
at net.minecraft.item.ItemStack.func_179546_a(ItemStack.java:186) ~[aip.class:?]
at net.minecraft.server.management.PlayerInteractionManager.func_187251_a(PlayerInteractionManager.java:478) ~[or.class:?]
at net.minecraft.network.NetHandlerPlayServer.func_184337_a(NetHandlerPlayServer.java:739) ~[pa.class:?]
at net.minecraft.network.play.client.CPacketPlayerTryUseItemOnBlock.func_148833_a(SourceFile:55) ~[ma.class:?]
at net.minecraft.network.play.client.CPacketPlayerTryUseItemOnBlock.func_148833_a(SourceFile:11) ~[ma.class:?]
at net.minecraft.network.PacketThreadUtil$1.run(SourceFile:13) ~[hv$1.class:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_151]
at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_151]
at net.minecraft.util.Util.func_181617_a(SourceFile:46) ~[h.class:?]
... 5 more
[18:36:19] [main/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NoClassDefFoundError: Could not initialize class org.dimdev.ddutils.lsystem.LSystem
at java.util.concurrent.FutureTask.report(Unknown Source) ~[?:1.8.0_151]
at java.util.concurrent.FutureTask.get(Unknown Source) ~[?:1.8.0_151]
at net.minecraft.util.Util.func_181617_a(SourceFile:47) [h.class:?]
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:1086) [bib.class:?]
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:397) [bib.class:?]
at net.minecraft.client.main.Main.main(SourceFile:123) [Main.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_151]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_151]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_151]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_151]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_151]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_151]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_151]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_151]
at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:236) [NewLaunch.jar:?]
at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:297) [NewLaunch.jar:?]
at org.multimc.EntryPoint.listen(EntryPoint.java:162) [NewLaunch.jar:?]
at org.multimc.EntryPoint.main(EntryPoint.java:53) [NewLaunch.jar:?]
Caused by: java.lang.NoClassDefFoundError: Could not initialize class org.dimdev.ddutils.lsystem.LSystem
at org.dimdev.dimdoors.shared.tileentities.TileEntityFloatingRift.(TileEntityFloatingRift.java:46) ~[TileEntityFloatingRift.class:?]
at org.dimdev.dimdoors.shared.blocks.BlockFloatingRift.createNewTileEntity(BlockFloatingRift.java:43) ~[BlockFloatingRift.class:?]
at org.dimdev.dimdoors.shared.blocks.BlockFloatingRift.func_149915_a(BlockFloatingRift.java:28) ~[BlockFloatingRift.class:?]
at net.minecraft.block.Block.createTileEntity(Block.java:1274) ~[aow.class:?]
at net.minecraft.world.chunk.Chunk.func_177436_a(Chunk.java:623) ~[axw.class:?]
at net.minecraft.world.World.func_180501_a(World.java:342) ~[amu.class:?]
at net.minecraft.client.multiplayer.WorldClient.func_180503_b(WorldClient.java:366) ~[bsb.class:?]
at net.minecraft.client.network.NetHandlerPlayClient.func_147234_a(NetHandlerPlayClient.java:774) ~[brz.class:?]
at net.minecraft.network.play.server.SPacketBlockChange.func_148833_a(SourceFile:40) ~[ij.class:?]
at net.minecraft.network.play.server.SPacketBlockChange.func_148833_a(SourceFile:13) ~[ij.class:?]
at net.minecraft.network.PacketThreadUtil$1.run(SourceFile:13) ~[hv$1.class:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_151]
at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_151]
at net.minecraft.util.Util.func_181617_a(SourceFile:46) ~[h.class:?]
... 17 more

Excuse me for not reading the stacktrace correctly. So what is the problem here? Does Minecraft include its own outdated version of slf4j or does the library not end up in the DimDoors jar file somehow?

@Runemoro is Minecraft, perchance, including a higher version of slf4j than we are including via gradle? Because our version certainly isn't the latest.

Also, we aren't actually calling slf4j anywhere in our code, so why is it in our build.gradle at all?

@Robijnvogel It's included because poly2tri depends on it (which doesn't use gradle, so we have to manually add its dependencies).

The library is in the jar, and a search for slf4j returns nothing in the Minecraft code.

Fixed.