I am making a sky grid generator but I am having trouble grabbing random materials to set for the chunk generator. Here is my code: Code (Java): public class GridGenerator extends ChunkGenerator { private int materialSize = Material.values().length; @Override public ChunkData generateChunkData(World world, Random random, int x, int z, BiomeGrid biome) { ChunkData data = createChunkData(world); Material material; for (int X = 0; X < 8; X++) { for (int Z = 0; Z < 8; Z++) { for (int Y = 0; Y < 128; Y++) { material = Material.values()[random.nextInt(materialSize)]; while (!material.isBlock() || material.isAir()) { material = Material.values()[random.nextInt(materialSize)]; } data.setBlock(X*2, Y*2, Z*2, material); } } } return data; } } I am getting a strange error that does not point to my code but is somehow caused by it: Code (Text): [13:23:49 ERROR]: Encountered an unexpected exception net.minecraft.server.v1_15_R1.ReportedException: Exception generating new chunk at net.minecraft.server.v1_15_R1.MinecraftServer.initWorld(MinecraftServer.java:515) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.MinecraftServer.a(MinecraftServer.java:451) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.DedicatedServer.init(DedicatedServer.java:290) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.MinecraftServer.run(MinecraftServer.java:884) ~[patched_1.15.1.jar:git-Paper-30] at java.lang.Thread.run(Unknown Source) [?:1.8.0_231] Caused by: java.lang.NullPointerException at net.minecraft.server.v1_15_R1.ProtoChunk.setTileEntity(ProtoChunk.java:230) ~[patched_1.15.1.jar:git-Paper-30] at org.bukkit.craftbukkit.v1_15_R1.generator.CustomChunkGenerator.buildBase(CustomChunkGenerator.java:135) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.ChunkStatus.lambda$static$6(ChunkStatus.java:51) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.ChunkStatus$d.doWork(ChunkStatus.java:240) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.ChunkStatus.a(ChunkStatus.java:186) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.PlayerChunkMap.lambda$null$20(PlayerChunkMap.java:672) ~[patched_1.15.1.jar:git-Paper-30] at com.mojang.datafixers.util.Either$Left.map(Either.java:38) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.PlayerChunkMap.lambda$b$22(PlayerChunkMap.java:670) ~[patched_1.15.1.jar:git-Paper-30] at java.util.concurrent.CompletableFuture.uniCompose(Unknown Source) ~[?:1.8.0_231] at java.util.concurrent.CompletableFuture$UniCompose.tryFire(Unknown Source) ~[?:1.8.0_231] at java.util.concurrent.CompletableFuture$Completion.run(Unknown Source) ~[?:1.8.0_231] at net.minecraft.server.v1_15_R1.ChunkTaskQueueSorter.b(SourceFile:58) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.ThreadedMailbox.e(SourceFile:83) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.ThreadedMailbox.a(SourceFile:123) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.ThreadedMailbox.run(SourceFile:91) ~[patched_1.15.1.jar:git-Paper-30] at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(Unknown Source) ~[?:1.8.0_231] at java.util.concurrent.ForkJoinTask.doExec(Unknown Source) ~[?:1.8.0_231] at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(Unknown Source) ~[?:1.8.0_231] at java.util.concurrent.ForkJoinPool.runWorker(Unknown Source) ~[?:1.8.0_231] at java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source) ~[?:1.8.0_231] [13:23:49 ERROR]: Cause of unexpected exception was java.lang.NullPointerException: null at net.minecraft.server.v1_15_R1.ProtoChunk.setTileEntity(ProtoChunk.java:230) ~[patched_1.15.1.jar:git-Paper-30] at org.bukkit.craftbukkit.v1_15_R1.generator.CustomChunkGenerator.buildBase(CustomChunkGenerator.java:135) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.ChunkStatus.lambda$static$6(ChunkStatus.java:51) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.ChunkStatus$d.doWork(ChunkStatus.java:240) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.ChunkStatus.a(ChunkStatus.java:186) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.PlayerChunkMap.lambda$null$20(PlayerChunkMap.java:672) ~[patched_1.15.1.jar:git-Paper-30] at com.mojang.datafixers.util.Either$Left.map(Either.java:38) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.PlayerChunkMap.lambda$b$22(PlayerChunkMap.java:670) ~[patched_1.15.1.jar:git-Paper-30] at java.util.concurrent.CompletableFuture.uniCompose(Unknown Source) ~[?:1.8.0_231] at java.util.concurrent.CompletableFuture$UniCompose.tryFire(Unknown Source) ~[?:1.8.0_231] at java.util.concurrent.CompletableFuture$Completion.run(Unknown Source) ~[?:1.8.0_231] at net.minecraft.server.v1_15_R1.ChunkTaskQueueSorter.b(SourceFile:58) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.ThreadedMailbox.e(SourceFile:83) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.ThreadedMailbox.a(SourceFile:123) ~[patched_1.15.1.jar:git-Paper-30] at net.minecraft.server.v1_15_R1.ThreadedMailbox.run(SourceFile:91) ~[patched_1.15.1.jar:git-Paper-30] at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(Unknown Source) ~[?:1.8.0_231] at java.util.concurrent.ForkJoinTask.doExec(Unknown Source) ~[?:1.8.0_231] at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(Unknown Source) ~[?:1.8.0_231] at java.util.concurrent.ForkJoinPool.runWorker(Unknown Source) ~[?:1.8.0_231] at java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source) ~[?:1.8.0_231] The closest thing I can think of given the error is tile entities are causing it however when I tried filtering out material tile entities I failed.
Try to do this: Code (Text): public class GridGenerator extends ChunkGenerator { @Override public ChunkData generateChunkData(World world, Random random, int x, int z, BiomeGrid biome) { ChunkData data = createChunkData(world); Material material; for (int X = 0; X < 8; X++) { for (int Z = 0; Z < 8; Z++) { for (int Y = 0; Y < 128; Y++) { do { material = Material.values[random.nextInt(Material.values().length)]; } while (!material.isBlock() || material.isAir() || material == null) data.setBlock(X*2, Y*2, Z*2, material); } } } return data; } }
