The error occur when a splatter map is placed, on Paper 1.18.1 (still experimental atm).
[12:25:50 ERROR]: [ImageOnMap] Unable to get Splatter Map attribute on item
fr.zcraft.imageonmap.quartzlib.tools.reflection.NMSException: Unable to find class: ItemStack
at fr.zcraft.imageonmap.quartzlib.components.nbt.NBT.getMinecraftClass(NBT.java:248) ~[ImageOnMap-4.1.2.jar:?]
at fr.zcraft.imageonmap.quartzlib.components.nbt.NBT.init(NBT.java:265) ~[ImageOnMap-4.1.2.jar:?]
at fr.zcraft.imageonmap.quartzlib.components.nbt.NBT.fromItemStack(NBT.java:72) ~[ImageOnMap-4.1.2.jar:?]
at fr.moribus.imageonmap.ui.SplatterMapManager.hasSplatterAttributes(SplatterMapManager.java:155) ~[ImageOnMap-4.1.2.jar:?]
at fr.moribus.imageonmap.ui.MapItemManager.onItemFramePlace(MapItemManager.java:255) ~[ImageOnMap-4.1.2.jar:?]
at fr.moribus.imageonmap.ui.MapItemManager.onEntityInteract(MapItemManager.java:349) ~[ImageOnMap-4.1.2.jar:?]
at com.destroystokyo.paper.event.executor.StaticMethodHandleEventExecutor.execute(StaticMethodHandleEventExecutor.java:38) ~[paper-api-1.18.1-R0.1-SNAPSHOT.jar:?]
at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:80) ~[paper-api-1.18.1-R0.1-SNAPSHOT.jar:git-Paper-75]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:70) ~[paper-api-1.18.1-R0.1-SNAPSHOT.jar:?]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:628) ~[paper-api-1.18.1-R0.1-SNAPSHOT.jar:?]
at net.minecraft.server.network.ServerGamePacketListenerImpl$5.performInteraction(ServerGamePacketListenerImpl.java:2437) ~[?:?]
at net.minecraft.server.network.ServerGamePacketListenerImpl$5.a(ServerGamePacketListenerImpl.java:2487) ~[?:?]
at net.minecraft.network.protocol.game.ServerboundInteractPacket$InteractionAction.dispatch(ServerboundInteractPacket.java:131) ~[?:?]
at net.minecraft.network.protocol.game.ServerboundInteractPacket.dispatch(ServerboundInteractPacket.java:80) ~[?:?]
at net.minecraft.server.network.ServerGamePacketListenerImpl.handleInteract(ServerGamePacketListenerImpl.java:2429) ~[?:?]
at net.minecraft.network.protocol.game.ServerboundInteractPacket.handle(ServerboundInteractPacket.java:67) ~[?:?]
at net.minecraft.network.protocol.game.ServerboundInteractPacket.handle(ServerboundInteractPacket.java:12) ~[?:?]
at net.minecraft.network.protocol.PacketUtils.lambda$ensureRunningOnSameThread$1(PacketUtils.java:56) ~[?:?]
at net.minecraft.server.TickTask.run(TickTask.java:18) ~[paper-1.18.1.jar:git-Paper-75]
at net.minecraft.util.thread.BlockableEventLoop.doRunTask(BlockableEventLoop.java:149) ~[?:?]
at net.minecraft.util.thread.ReentrantBlockableEventLoop.doRunTask(ReentrantBlockableEventLoop.java:23) ~[?:?]
at net.minecraft.server.MinecraftServer.doRunTask(MinecraftServer.java:1413) ~[paper-1.18.1.jar:git-Paper-75]
at net.minecraft.server.MinecraftServer.c(MinecraftServer.java:189) ~[paper-1.18.1.jar:git-Paper-75]
at net.minecraft.util.thread.BlockableEventLoop.pollTask(BlockableEventLoop.java:122) ~[?:?]
at net.minecraft.server.MinecraftServer.pollTaskInternal(MinecraftServer.java:1391) ~[paper-1.18.1.jar:git-Paper-75]
at net.minecraft.server.MinecraftServer.pollTask(MinecraftServer.java:1384) ~[paper-1.18.1.jar:git-Paper-75]
at net.minecraft.util.thread.BlockableEventLoop.managedBlock(BlockableEventLoop.java:132) ~[?:?]
at net.minecraft.server.MinecraftServer.waitUntilNextTick(MinecraftServer.java:1362) ~[paper-1.18.1.jar:git-Paper-75]
at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1268) ~[paper-1.18.1.jar:git-Paper-75]
at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:317) ~[paper-1.18.1.jar:git-Paper-75]
at java.lang.Thread.run(Thread.java:833) ~[?:?]
Caused by: java.lang.ClassNotFoundException: net.minecraft.server.v1_18_R1.ItemStack
at org.bukkit.plugin.java.PluginClassLoader.loadClass0(PluginClassLoader.java:151) ~[paper-api-1.18.1-R0.1-SNAPSHOT.jar:?]
at org.bukkit.plugin.java.PluginClassLoader.loadClass(PluginClassLoader.java:103) ~[paper-api-1.18.1-R0.1-SNAPSHOT.jar:?]
at java.lang.ClassLoader.loadClass(ClassLoader.java:520) ~[?:?]
at java.lang.Class.forName0(Native Method) ~[?:?]
at java.lang.Class.forName(Class.java:375) ~[?:?]
at fr.zcraft.imageonmap.quartzlib.tools.reflection.Reflection.getMinecraftClassByName(Reflection.java:106) ~[ImageOnMap-4.1.2.jar:?]
at fr.zcraft.imageonmap.quartzlib.components.nbt.NBT.getMinecraftClass(NBT.java:246) ~[ImageOnMap-4.1.2.jar:?]
... 30 more
The error occur when a splatter map is placed, on Paper 1.18.1 (still experimental atm).