When starting the server with the plugin installed it throws the above mentioned error.
Running CraftBukkit 1.14.4 and FactionMobs v3.3.4_1.14.4-R0.1.
The error.log states
[2019/09/20 20:48:24] java.lang.NoSuchMethodException: net.minecraft.server.v1_14_R1.EntityPositionTypes.a(net.minecraft.server.v1_14_R1.EntityTypes, net.minecraft.server.v1_14_R1.EntityPositionTypes$Surface, net.minecraft.server.v1_14_R1.HeightMap$Type)
at java.base/java.lang.Class.getDeclaredMethod(Class.java:2475)
at com.gmail.scyntrus.fmob.ReflectionManager.init(ReflectionManager.java:23)
at com.gmail.scyntrus.fmob.FactionMobs.onEnable(FactionMobs.java:158)
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:263)
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:344)
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:416)
at org.bukkit.craftbukkit.v1_14_R1.CraftServer.enablePlugin(CraftServer.java:447)
at org.bukkit.craftbukkit.v1_14_R1.CraftServer.enablePlugins(CraftServer.java:373)
at org.bukkit.craftbukkit.v1_14_R1.CraftServer.reload(CraftServer.java:786)
at org.bukkit.Bukkit.reload(Bukkit.java:585)
at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:27)
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:148)
at org.bukkit.craftbukkit.v1_14_R1.CraftServer.dispatchCommand(CraftServer.java:689)
at org.bukkit.craftbukkit.v1_14_R1.CraftServer.dispatchServerCommand(CraftServer.java:675)
at net.minecraft.server.v1_14_R1.DedicatedServer.handleCommandQueue(DedicatedServer.java:416)
at net.minecraft.server.v1_14_R1.DedicatedServer.b(DedicatedServer.java:381)
at net.minecraft.server.v1_14_R1.MinecraftServer.a(MinecraftServer.java:926)
at net.minecraft.server.v1_14_R1.MinecraftServer.run(MinecraftServer.java:780)
at java.base/java.lang.Thread.run(Thread.java:834)
Following the code it looks like
EntityPositionType.a(EntityTypes<T>, EntityPositionTypes.Surface, HeightMap.Type)
got changed to
EntityPositionType.a(EntityTypes<T>, EntityPositionTypes.Surface, HeightMap.Type, EntityPositionTypes.b<T>)
in 1.14.3.
When starting the server with the plugin installed it throws the above mentioned error.
Running CraftBukkit 1.14.4 and FactionMobs v3.3.4_1.14.4-R0.1.
The error.log states
Following the code it looks like
EntityPositionType.a(EntityTypes<T>, EntityPositionTypes.Surface, HeightMap.Type)
got changed toEntityPositionType.a(EntityTypes<T>, EntityPositionTypes.Surface, HeightMap.Type, EntityPositionTypes.b<T>)
in 1.14.3.