use correct types for preloading CraftRegistry

also add a check in CraftRegistryEntry constructor to
make sure preload class isn't in net.minecraft package

patches/server/0471-Add-RegistryAccess-for-managing-Registries.patch

@@ -12,7 +12,7 @@ public net.minecraft.server.RegistryLayer STATIC_ACCESS
 
 diff --git a/src/main/java/io/papermc/paper/registry/PaperRegistries.java b/src/main/java/io/papermc/paper/registry/PaperRegistries.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..c92ce42398a9bfd00eb4e05972289c521ee255cf
+index 0000000000000000000000000000000000000000..633b01431750d4b40159a57bf25fb35c6670ff1b
 --- /dev/null
 +++ b/src/main/java/io/papermc/paper/registry/PaperRegistries.java
 @@ -0,0 +1,146 @@
@@ -28,8 +28,6 @@ index 0000000000000000000000000000000000000000..c92ce42398a9bfd00eb4e05972289c52
 +import net.minecraft.core.Registry;
 +import net.minecraft.core.registries.Registries;
 +import net.minecraft.resources.ResourceKey;
-+import net.minecraft.world.item.enchantment.Enchantment;
-+import net.minecraft.world.level.levelgen.structure.Structure;
 +import org.bukkit.GameEvent;
 +import org.bukkit.JukeboxSong;
 +import org.bukkit.Keyed;
@@ -58,11 +56,13 @@ index 0000000000000000000000000000000000000000..c92ce42398a9bfd00eb4e05972289c52
 +import org.bukkit.craftbukkit.potion.CraftPotionEffectType;
 +import org.bukkit.craftbukkit.util.CraftNamespacedKey;
 +import org.bukkit.damage.DamageType;
++import org.bukkit.enchantments.Enchantment;
 +import org.bukkit.entity.Cat;
 +import org.bukkit.entity.Frog;
 +import org.bukkit.entity.Villager;
 +import org.bukkit.entity.Wolf;
 +import org.bukkit.entity.memory.MemoryKey;
++import org.bukkit.generator.structure.Structure;
 +import org.bukkit.generator.structure.StructureType;
 +import org.bukkit.inventory.ItemType;
 +import org.bukkit.inventory.MenuType;
@@ -416,12 +416,13 @@ index 0000000000000000000000000000000000000000..ceb217dbbb84e8bd51365dd47bf91971
 +}
 diff --git a/src/main/java/io/papermc/paper/registry/entry/CraftRegistryEntry.java b/src/main/java/io/papermc/paper/registry/entry/CraftRegistryEntry.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..568984894a5463ccfa68bb6944b409ab0a2d7ad7
+index 0000000000000000000000000000000000000000..9bb4aa926978f117901c9f99c45a6862a1d5ce30
 --- /dev/null
 +++ b/src/main/java/io/papermc/paper/registry/entry/CraftRegistryEntry.java
-@@ -0,0 +1,49 @@
+@@ -0,0 +1,51 @@
 +package io.papermc.paper.registry.entry;
 +
++import com.google.common.base.Preconditions;
 +import io.papermc.paper.registry.RegistryHolder;
 +import io.papermc.paper.registry.RegistryKey;
 +import java.util.function.BiFunction;
@@ -450,6 +451,7 @@ index 0000000000000000000000000000000000000000..568984894a5463ccfa68bb6944b409ab
 +        final BiFunction<NamespacedKey, M, B> minecraftToBukkit
 +    ) {
 +        super(mcKey, apiKey);
++        Preconditions.checkArgument(!classToPreload.getPackageName().startsWith("net.minecraft"), classToPreload + " should not be in the net.minecraft package as the class-to-preload");
 +        this.classToPreload = classToPreload;
 +        this.minecraftToBukkit = minecraftToBukkit;
 +    }