Make OldEnum and Particle interface for easier implementation

src/main/java/org/bukkit/Art.java

@@ -13,7 +13,7 @@ import org.jetbrains.annotations.Nullable;
  * Represents the art on a painting.
  * Listed Arts are present at the default server.
  */
-public abstract class Art extends OldEnum<Art> implements Keyed {
+public abstract class Art implements OldEnum<Art>, Keyed {
     @Deprecated
     private static final Map<Integer, Art> BY_ID = Maps.newHashMap();
 

src/main/java/org/bukkit/Fluid.java

@@ -9,7 +9,7 @@ import org.jetbrains.annotations.NotNull;
 /**
  * Represents a fluid type.
  */
-public abstract class Fluid extends OldEnum<Fluid> implements Keyed {
+public abstract class Fluid implements OldEnum<Fluid>, Keyed {
 
     /**
      * Empty.

src/main/java/org/bukkit/Particle.java

@@ -10,14 +10,14 @@ import org.bukkit.util.OldEnum;
 import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 
-public abstract class Particle extends OldEnum<Particle> implements Keyed {
+public interface Particle extends OldEnum<Particle>, Keyed {
 
     /**
      * Typed represents a subtype of {@link Particle particles} that have a data type.
      *
      * @param <D> the generic data type of the particle.
      */
-    public abstract static class Typed<D> extends Particle {
+    interface Typed<D> extends Particle {
 
         /**
          * Returns the required data type for the particle
@@ -26,178 +26,178 @@ public abstract class Particle extends OldEnum<Particle> implements Keyed {
          */
         @NotNull
         @Override
-        public abstract Class<D> getDataType();
+        Class<D> getDataType();
     }
 
-    public static final Particle POOF = getParticle("poof");
+    Particle POOF = getParticle("poof");
-    public static final Particle EXPLOSION = getParticle("explosion");
+    Particle EXPLOSION = getParticle("explosion");
-    public static final Particle EXPLOSION_EMITTER = getParticle("explosion_emitter");
+    Particle EXPLOSION_EMITTER = getParticle("explosion_emitter");
-    public static final Particle FIREWORK = getParticle("firework");
+    Particle FIREWORK = getParticle("firework");
-    public static final Particle BUBBLE = getParticle("bubble");
+    Particle BUBBLE = getParticle("bubble");
-    public static final Particle SPLASH = getParticle("splash");
+    Particle SPLASH = getParticle("splash");
-    public static final Particle FISHING = getParticle("fishing");
+    Particle FISHING = getParticle("fishing");
-    public static final Particle UNDERWATER = getParticle("underwater");
+    Particle UNDERWATER = getParticle("underwater");
-    public static final Particle CRIT = getParticle("crit");
+    Particle CRIT = getParticle("crit");
-    public static final Particle ENCHANTED_HIT = getParticle("enchanted_hit");
+    Particle ENCHANTED_HIT = getParticle("enchanted_hit");
-    public static final Particle SMOKE = getParticle("smoke");
+    Particle SMOKE = getParticle("smoke");
-    public static final Particle LARGE_SMOKE = getParticle("large_smoke");
+    Particle LARGE_SMOKE = getParticle("large_smoke");
-    public static final Particle EFFECT = getParticle("effect");
+    Particle EFFECT = getParticle("effect");
-    public static final Particle INSTANT_EFFECT = getParticle("instant_effect");
+    Particle INSTANT_EFFECT = getParticle("instant_effect");
     /**
      * Uses {@link Color} as DataType
      */
-    public static final Particle.Typed<Color> ENTITY_EFFECT = getParticle("entity_effect");
+    Particle.Typed<Color> ENTITY_EFFECT = getParticle("entity_effect");
-    public static final Particle AMBIENT_ENTITY_EFFECT = getParticle("ambient_entity_effect");
+    Particle AMBIENT_ENTITY_EFFECT = getParticle("ambient_entity_effect");
-    public static final Particle WITCH = getParticle("witch");
+    Particle WITCH = getParticle("witch");
-    public static final Particle DRIPPING_WATER = getParticle("dripping_water");
+    Particle DRIPPING_WATER = getParticle("dripping_water");
-    public static final Particle DRIPPING_LAVA = getParticle("dripping_lava");
+    Particle DRIPPING_LAVA = getParticle("dripping_lava");
-    public static final Particle ANGRY_VILLAGER = getParticle("angry_villager");
+    Particle ANGRY_VILLAGER = getParticle("angry_villager");
-    public static final Particle HAPPY_VILLAGER = getParticle("happy_villager");
+    Particle HAPPY_VILLAGER = getParticle("happy_villager");
-    public static final Particle MYCELIUM = getParticle("mycelium");
+    Particle MYCELIUM = getParticle("mycelium");
-    public static final Particle NOTE = getParticle("note");
+    Particle NOTE = getParticle("note");
-    public static final Particle PORTAL = getParticle("portal");
+    Particle PORTAL = getParticle("portal");
-    public static final Particle ENCHANT = getParticle("enchant");
+    Particle ENCHANT = getParticle("enchant");
-    public static final Particle FLAME = getParticle("flame");
+    Particle FLAME = getParticle("flame");
-    public static final Particle LAVA = getParticle("lava");
+    Particle LAVA = getParticle("lava");
-    public static final Particle CLOUD = getParticle("cloud");
+    Particle CLOUD = getParticle("cloud");
     /**
      * Uses {@link Particle.DustOptions} as DataType
      */
-    public static final Particle.Typed<DustOptions> DUST = getParticle("dust");
+    Particle.Typed<DustOptions> DUST = getParticle("dust");
-    public static final Particle ITEM_SNOWBALL = getParticle("item_snowball");
+    Particle ITEM_SNOWBALL = getParticle("item_snowball");
-    public static final Particle ITEM_SLIME = getParticle("item_slime");
+    Particle ITEM_SLIME = getParticle("item_slime");
-    public static final Particle HEART = getParticle("heart");
+    Particle HEART = getParticle("heart");
     /**
      * Uses {@link ItemStack} as DataType
      */
-    public static final Particle.Typed<ItemStack> ITEM = getParticle("item");
+    Particle.Typed<ItemStack> ITEM = getParticle("item");
     /**
      * Uses {@link BlockData} as DataType
      */
-    public static final Particle.Typed<BlockData> BLOCK = getParticle("block");
+    Particle.Typed<BlockData> BLOCK = getParticle("block");
-    public static final Particle RAIN = getParticle("rain");
+    Particle RAIN = getParticle("rain");
-    public static final Particle ELDER_GUARDIAN = getParticle("elder_guardian");
+    Particle ELDER_GUARDIAN = getParticle("elder_guardian");
-    public static final Particle DRAGON_BREATH = getParticle("dragon_breath");
+    Particle DRAGON_BREATH = getParticle("dragon_breath");
-    public static final Particle END_ROD = getParticle("end_rod");
+    Particle END_ROD = getParticle("end_rod");
-    public static final Particle DAMAGE_INDICATOR = getParticle("damage_indicator");
+    Particle DAMAGE_INDICATOR = getParticle("damage_indicator");
-    public static final Particle SWEEP_ATTACK = getParticle("sweep_attack");
+    Particle SWEEP_ATTACK = getParticle("sweep_attack");
     /**
      * Uses {@link BlockData} as DataType
      */
-    public static final Particle.Typed<BlockData> FALLING_DUST = getParticle("falling_dust");
+    Particle.Typed<BlockData> FALLING_DUST = getParticle("falling_dust");
-    public static final Particle TOTEM_OF_UNDYING = getParticle("totem_of_undying");
+    Particle TOTEM_OF_UNDYING = getParticle("totem_of_undying");
-    public static final Particle SPIT = getParticle("spit");
+    Particle SPIT = getParticle("spit");
-    public static final Particle SQUID_INK = getParticle("squid_ink");
+    Particle SQUID_INK = getParticle("squid_ink");
-    public static final Particle BUBBLE_POP = getParticle("bubble_pop");
+    Particle BUBBLE_POP = getParticle("bubble_pop");
-    public static final Particle CURRENT_DOWN = getParticle("current_down");
+    Particle CURRENT_DOWN = getParticle("current_down");
-    public static final Particle BUBBLE_COLUMN_UP = getParticle("bubble_column_up");
+    Particle BUBBLE_COLUMN_UP = getParticle("bubble_column_up");
-    public static final Particle NAUTILUS = getParticle("nautilus");
+    Particle NAUTILUS = getParticle("nautilus");
-    public static final Particle DOLPHIN = getParticle("dolphin");
+    Particle DOLPHIN = getParticle("dolphin");
-    public static final Particle SNEEZE = getParticle("sneeze");
+    Particle SNEEZE = getParticle("sneeze");
-    public static final Particle CAMPFIRE_COSY_SMOKE = getParticle("campfire_cosy_smoke");
+    Particle CAMPFIRE_COSY_SMOKE = getParticle("campfire_cosy_smoke");
-    public static final Particle CAMPFIRE_SIGNAL_SMOKE = getParticle("campfire_signal_smoke");
+    Particle CAMPFIRE_SIGNAL_SMOKE = getParticle("campfire_signal_smoke");
-    public static final Particle COMPOSTER = getParticle("composter");
+    Particle COMPOSTER = getParticle("composter");
-    public static final Particle FLASH = getParticle("flash");
+    Particle FLASH = getParticle("flash");
-    public static final Particle FALLING_LAVA = getParticle("falling_lava");
+    Particle FALLING_LAVA = getParticle("falling_lava");
-    public static final Particle LANDING_LAVA = getParticle("landing_lava");
+    Particle LANDING_LAVA = getParticle("landing_lava");
-    public static final Particle FALLING_WATER = getParticle("falling_water");
+    Particle FALLING_WATER = getParticle("falling_water");
-    public static final Particle DRIPPING_HONEY = getParticle("dripping_honey");
+    Particle DRIPPING_HONEY = getParticle("dripping_honey");
-    public static final Particle FALLING_HONEY = getParticle("falling_honey");
+    Particle FALLING_HONEY = getParticle("falling_honey");
-    public static final Particle LANDING_HONEY = getParticle("landing_honey");
+    Particle LANDING_HONEY = getParticle("landing_honey");
-    public static final Particle FALLING_NECTAR = getParticle("falling_nectar");
+    Particle FALLING_NECTAR = getParticle("falling_nectar");
-    public static final Particle SOUL_FIRE_FLAME = getParticle("soul_fire_flame");
+    Particle SOUL_FIRE_FLAME = getParticle("soul_fire_flame");
-    public static final Particle ASH = getParticle("ash");
+    Particle ASH = getParticle("ash");
-    public static final Particle CRIMSON_SPORE = getParticle("crimson_spore");
+    Particle CRIMSON_SPORE = getParticle("crimson_spore");
-    public static final Particle WARPED_SPORE = getParticle("warped_spore");
+    Particle WARPED_SPORE = getParticle("warped_spore");
-    public static final Particle SOUL = getParticle("soul");
+    Particle SOUL = getParticle("soul");
-    public static final Particle DRIPPING_OBSIDIAN_TEAR = getParticle("dripping_obsidian_tear");
+    Particle DRIPPING_OBSIDIAN_TEAR = getParticle("dripping_obsidian_tear");
-    public static final Particle FALLING_OBSIDIAN_TEAR = getParticle("falling_obsidian_tear");
+    Particle FALLING_OBSIDIAN_TEAR = getParticle("falling_obsidian_tear");
-    public static final Particle LANDING_OBSIDIAN_TEAR = getParticle("landing_obsidian_tear");
+    Particle LANDING_OBSIDIAN_TEAR = getParticle("landing_obsidian_tear");
-    public static final Particle REVERSE_PORTAL = getParticle("reverse_portal");
+    Particle REVERSE_PORTAL = getParticle("reverse_portal");
-    public static final Particle WHITE_ASH = getParticle("white_ash");
+    Particle WHITE_ASH = getParticle("white_ash");
     /**
      * Uses {@link DustTransition} as DataType
      */
-    public static final Particle.Typed<DustTransition> DUST_COLOR_TRANSITION = getParticle("dust_color_transition");
+    Particle.Typed<DustTransition> DUST_COLOR_TRANSITION = getParticle("dust_color_transition");
     /**
      * Uses {@link Vibration} as DataType
      */
-    public static final Particle.Typed<Vibration> VIBRATION = getParticle("vibration");
+    Particle.Typed<Vibration> VIBRATION = getParticle("vibration");
-    public static final Particle FALLING_SPORE_BLOSSOM = getParticle("falling_spore_blossom");
+    Particle FALLING_SPORE_BLOSSOM = getParticle("falling_spore_blossom");
-    public static final Particle SPORE_BLOSSOM_AIR = getParticle("spore_blossom_air");
+    Particle SPORE_BLOSSOM_AIR = getParticle("spore_blossom_air");
-    public static final Particle SMALL_FLAME = getParticle("small_flame");
+    Particle SMALL_FLAME = getParticle("small_flame");
-    public static final Particle SNOWFLAKE = getParticle("snowflake");
+    Particle SNOWFLAKE = getParticle("snowflake");
-    public static final Particle DRIPPING_DRIPSTONE_LAVA = getParticle("dripping_dripstone_lava");
+    Particle DRIPPING_DRIPSTONE_LAVA = getParticle("dripping_dripstone_lava");
-    public static final Particle FALLING_DRIPSTONE_LAVA = getParticle("falling_dripstone_lava");
+    Particle FALLING_DRIPSTONE_LAVA = getParticle("falling_dripstone_lava");
-    public static final Particle DRIPPING_DRIPSTONE_WATER = getParticle("dripping_dripstone_water");
+    Particle DRIPPING_DRIPSTONE_WATER = getParticle("dripping_dripstone_water");
-    public static final Particle FALLING_DRIPSTONE_WATER = getParticle("falling_dripstone_water");
+    Particle FALLING_DRIPSTONE_WATER = getParticle("falling_dripstone_water");
-    public static final Particle GLOW_SQUID_INK = getParticle("glow_squid_ink");
+    Particle GLOW_SQUID_INK = getParticle("glow_squid_ink");
-    public static final Particle GLOW = getParticle("glow");
+    Particle GLOW = getParticle("glow");
-    public static final Particle WAX_ON = getParticle("wax_on");
+    Particle WAX_ON = getParticle("wax_on");
-    public static final Particle WAX_OFF = getParticle("wax_off");
+    Particle WAX_OFF = getParticle("wax_off");
-    public static final Particle ELECTRIC_SPARK = getParticle("electric_spark");
+    Particle ELECTRIC_SPARK = getParticle("electric_spark");
-    public static final Particle SCRAPE = getParticle("scrape");
+    Particle SCRAPE = getParticle("scrape");
-    public static final Particle SONIC_BOOM = getParticle("sonic_boom");
+    Particle SONIC_BOOM = getParticle("sonic_boom");
-    public static final Particle SCULK_SOUL = getParticle("sculk_soul");
+    Particle SCULK_SOUL = getParticle("sculk_soul");
     /**
      * Use {@link Float} as DataType
      */
-    public static final Particle.Typed<Float> SCULK_CHARGE = getParticle("sculk_charge");
+    Particle.Typed<Float> SCULK_CHARGE = getParticle("sculk_charge");
-    public static final Particle SCULK_CHARGE_POP = getParticle("sculk_charge_pop");
+    Particle SCULK_CHARGE_POP = getParticle("sculk_charge_pop");
     /**
      * Use {@link Integer} as DataType
      */
-    public static final Particle.Typed<Integer> SHRIEK = getParticle("shriek");
+    Particle.Typed<Integer> SHRIEK = getParticle("shriek");
-    public static final Particle CHERRY_LEAVES = getParticle("cherry_leaves");
+    Particle CHERRY_LEAVES = getParticle("cherry_leaves");
-    public static final Particle EGG_CRACK = getParticle("egg_crack");
+    Particle EGG_CRACK = getParticle("egg_crack");
-    public static final Particle DUST_PLUME = getParticle("dust_plume");
+    Particle DUST_PLUME = getParticle("dust_plume");
-    public static final Particle WHITE_SMOKE = getParticle("white_smoke");
+    Particle WHITE_SMOKE = getParticle("white_smoke");
     @ApiStatus.Experimental
     @MinecraftExperimental(Requires.UPDATE_1_21)
-    public static final Particle GUST = getParticle("gust");
+    Particle GUST = getParticle("gust");
     @ApiStatus.Experimental
     @MinecraftExperimental(Requires.UPDATE_1_21)
-    public static final Particle SMALL_GUST = getParticle("small_gust");
+    Particle SMALL_GUST = getParticle("small_gust");
     @ApiStatus.Experimental
     @MinecraftExperimental(Requires.UPDATE_1_21)
-    public static final Particle GUST_EMITTER_LARGE = getParticle("gust_emitter_large");
+    Particle GUST_EMITTER_LARGE = getParticle("gust_emitter_large");
     @ApiStatus.Experimental
     @MinecraftExperimental(Requires.UPDATE_1_21)
-    public static final Particle GUST_EMITTER_SMALL = getParticle("gust_emitter_small");
+    Particle GUST_EMITTER_SMALL = getParticle("gust_emitter_small");
     @ApiStatus.Experimental
     @MinecraftExperimental(Requires.UPDATE_1_21)
-    public static final Particle TRIAL_SPAWNER_DETECTION = getParticle("trial_spawner_detection");
+    Particle TRIAL_SPAWNER_DETECTION = getParticle("trial_spawner_detection");
     @ApiStatus.Experimental
     @MinecraftExperimental(Requires.UPDATE_1_21)
-    public static final Particle TRIAL_SPAWNER_DETECTION_OMINOUS = getParticle("trial_spawner_detection_ominous");
+    Particle TRIAL_SPAWNER_DETECTION_OMINOUS = getParticle("trial_spawner_detection_ominous");
     @ApiStatus.Experimental
     @MinecraftExperimental(Requires.UPDATE_1_21)
-    public static final Particle VAULT_CONNECTION = getParticle("vault_connection");
+    Particle VAULT_CONNECTION = getParticle("vault_connection");
     @ApiStatus.Experimental
     @MinecraftExperimental(Requires.UPDATE_1_21)
-    public static final Particle INFESTED = getParticle("infested");
+    Particle INFESTED = getParticle("infested");
     @ApiStatus.Experimental
     @MinecraftExperimental(Requires.UPDATE_1_21)
-    public static final Particle ITEM_COBWEB = getParticle("item_cobweb");
+    Particle ITEM_COBWEB = getParticle("item_cobweb");
     /**
      * Uses {@link BlockData} as DataType
      */
     @ApiStatus.Experimental
     @MinecraftExperimental(Requires.UPDATE_1_21)
-    public static final Particle.Typed<BlockData> DUST_PILLAR = getParticle("dust_pillar");
+    Particle.Typed<BlockData> DUST_PILLAR = getParticle("dust_pillar");
     @ApiStatus.Experimental
     @MinecraftExperimental(Requires.UPDATE_1_21)
-    public static final Particle OMINOUS_SPAWNING = getParticle("ominous_spawning");
+    Particle OMINOUS_SPAWNING = getParticle("ominous_spawning");
     @ApiStatus.Experimental
     @MinecraftExperimental(Requires.UPDATE_1_21)
-    public static final Particle RAID_OMEN = getParticle("raid_omen");
+    Particle RAID_OMEN = getParticle("raid_omen");
     @ApiStatus.Experimental
     @MinecraftExperimental(Requires.UPDATE_1_21)
-    public static final Particle TRIAL_OMEN = getParticle("trial_omen");
+    Particle TRIAL_OMEN = getParticle("trial_omen");
     /**
      * Uses {@link BlockData} as DataType
      */
-    public static final Particle.Typed<BlockData> BLOCK_MARKER = getParticle("block_marker");
+    Particle.Typed<BlockData> BLOCK_MARKER = getParticle("block_marker");
 
     @NotNull
     private static <P extends Particle> P getParticle(@NotNull String key) {
@@ -220,7 +220,7 @@ public abstract class Particle extends OldEnum<Particle> implements Keyed {
      * @see #getDataType()
      */
     @NotNull
-    public abstract <D> Particle.Typed<D> typed(@NotNull Class<D> dataType);
+    <D> Particle.Typed<D> typed(@NotNull Class<D> dataType);
 
     /**
      * Returns true if this Particle is typed and requires extra data when spawning it.
@@ -229,7 +229,7 @@ public abstract class Particle extends OldEnum<Particle> implements Keyed {
      * @see #getDataType()
      * @see #typed(Class)
      */
-    public abstract boolean isTyped();
+    boolean isTyped();
 
     /**
      * Returns the required data type for the particle
@@ -240,7 +240,7 @@ public abstract class Particle extends OldEnum<Particle> implements Keyed {
      * @see #typed(Class)
      */
     @NotNull
-    public abstract Class<?> getDataType();
+    Class<?> getDataType();
 
     /**
      * Options which can be applied to redstone dust particles - a particle
@@ -309,7 +309,7 @@ public abstract class Particle extends OldEnum<Particle> implements Keyed {
      */
     @NotNull
     @Deprecated
-    public static Particle valueOf(@NotNull String name) {
+    static Particle valueOf(@NotNull String name) {
         Particle particle = Registry.PARTICLE_TYPE.get(NamespacedKey.fromString(name.toLowerCase(Locale.ROOT)));
         Preconditions.checkArgument(particle != null, "No particle found with the name %s", name);
         return particle;
@@ -321,7 +321,7 @@ public abstract class Particle extends OldEnum<Particle> implements Keyed {
      */
     @NotNull
     @Deprecated
-    public static Particle[] values() {
+    static Particle[] values() {
         return Lists.newArrayList(Registry.PARTICLE_TYPE).toArray(new Particle[0]);
     }
 }

src/main/java/org/bukkit/Statistic.java

@@ -9,7 +9,7 @@ import org.jetbrains.annotations.NotNull;
 /**
  * Represents a countable statistic, which is tracked by the server.
  */
-public abstract class Statistic extends OldEnum<Statistic> implements Keyed {
+public abstract class Statistic implements OldEnum<Statistic>, Keyed {
 
     public static final Statistic DAMAGE_DEALT = getStatistic("damage_dealt");
     public static final Statistic DAMAGE_TAKEN = getStatistic("damage_taken");

src/main/java/org/bukkit/attribute/Attribute.java

@@ -13,7 +13,7 @@ import org.jetbrains.annotations.NotNull;
 /**
  * Types of attributes which may be present on an {@link Attributable}.
  */
-public abstract class Attribute extends OldEnum<Attribute> implements Keyed, Translatable {
+public abstract class Attribute implements OldEnum<Attribute>, Keyed, Translatable {
 
     /**
      * Maximum health of an Entity.

src/main/java/org/bukkit/block/Biome.java

@@ -16,7 +16,7 @@ import org.jetbrains.annotations.NotNull;
  * Depending on the server there might be additional biomes present (for example biomes created by data packs),
  * which you can get via {@link Registry#BIOME}.
  */
-public abstract class Biome extends OldEnum<Biome> implements Keyed {
+public abstract class Biome implements OldEnum<Biome>, Keyed {
 
     public static final Biome OCEAN = getBiome("ocean");
     public static final Biome PLAINS = getBiome("plains");

src/main/java/org/bukkit/block/banner/PatternType.java

@@ -15,7 +15,7 @@ import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-public abstract class PatternType extends OldEnum<PatternType> implements Keyed {
+public abstract class PatternType implements OldEnum<PatternType>, Keyed {
     public static final PatternType BASE = getPatternType("base");
     public static final PatternType SQUARE_BOTTOM_LEFT = getPatternType("square_bottom_left");
     public static final PatternType SQUARE_BOTTOM_RIGHT = getPatternType("square_bottom_right");

src/main/java/org/bukkit/entity/Cat.java

@@ -48,7 +48,7 @@ public interface Cat extends Tameable, Sittable {
     /**
      * Represents the various different cat types there are.
      */
-    abstract class Type extends OldEnum<Type> implements Keyed {
+    abstract class Type implements OldEnum<Type>, Keyed {
         public static final Type TABBY = getType("tabby");
         public static final Type BLACK = getType("black");
         public static final Type RED = getType("red");

src/main/java/org/bukkit/entity/EntityType.java

@@ -30,7 +30,7 @@ import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-public abstract class EntityType extends OldEnum<EntityType> implements Keyed, Translatable {
+public abstract class EntityType implements OldEnum<EntityType>, Keyed, Translatable {
     private static final BiMap<Short, EntityType> ID_MAP = HashBiMap.create();
 
     /**

src/main/java/org/bukkit/entity/Frog.java

@@ -48,7 +48,7 @@ public interface Frog extends Animals {
     /**
      * Represents the variant of a frog - ie its color.
      */
-    abstract class Variant extends OldEnum<Variant> implements Keyed {
+    abstract class Variant implements OldEnum<Variant>, Keyed {
 
         /**
          * Temperate (brown-orange) frog.

src/main/java/org/bukkit/entity/Villager.java

@@ -122,7 +122,7 @@ public interface Villager extends AbstractVillager {
      * Represents Villager type, usually corresponding to what biome they spawn
      * in.
      */
-    public abstract class Type extends OldEnum<Type> implements Keyed {
+    public abstract class Type implements OldEnum<Type>, Keyed {
 
         public static final Type DESERT = getType("desert");
         public static final Type JUNGLE = getType("jungle");
@@ -168,7 +168,7 @@ public interface Villager extends AbstractVillager {
      * Represents the various different Villager professions there may be.
      * Villagers have different trading options depending on their profession,
      */
-    public abstract class Profession extends OldEnum<Profession> implements Keyed {
+    public abstract class Profession implements OldEnum<Profession>, Keyed {
         public static final Profession NONE = getProfession("none");
         /**
          * Armorer profession. Wears a black apron. Armorers primarily trade for

src/main/java/org/bukkit/potion/PotionType.java

@@ -17,7 +17,7 @@ import org.jetbrains.annotations.Nullable;
  * This class reflects and matches each potion state that can be obtained from
  * the Creative mode inventory
  */
-public abstract class PotionType extends OldEnum<PotionType> implements Keyed {
+public abstract class PotionType implements OldEnum<PotionType>, Keyed {
     public static final PotionType EMPTY = getPotionType("empty");
     public static final PotionType WATER = getPotionType("water");
     public static final PotionType MUNDANE = getPotionType("mundane");

src/main/java/org/bukkit/util/OldEnum.java

@@ -8,7 +8,7 @@ import org.jetbrains.annotations.NotNull;
  * @deprecated only for backwards compatibility.
  */
 @Deprecated
-public abstract class OldEnum<T extends OldEnum<T>> implements Comparable<T> {
+public interface OldEnum<T extends OldEnum<T>> extends Comparable<T> {
     /**
      * @param other to compare to.
      * @return negative if this old enum is lower, zero if equal and positive if higher than the given old enum.
@@ -16,7 +16,7 @@ public abstract class OldEnum<T extends OldEnum<T>> implements Comparable<T> {
      */
     @Deprecated
     @Override
-    public abstract int compareTo(@NotNull T other);
+    int compareTo(@NotNull T other);
 
     /**
      * @return the name of the old enum.
@@ -24,12 +24,12 @@ public abstract class OldEnum<T extends OldEnum<T>> implements Comparable<T> {
      */
     @NotNull
     @Deprecated
-    public abstract String name();
+    String name();
 
     /**
      * @return the ordinal of the old enum.
      * @deprecated only for backwards compatibility, it is not guaranteed that an old enum always has the same ordinal.
      */
     @Deprecated
-    public abstract int ordinal();
+    int ordinal();
 }