Ocelots do not spawn naturally on Peaceful difficulty in jungles and bamboo jungles

The bug

Despite being friendly mobs, ocelots will not spawn on peaceful in jungle or bamboo jungle biomes

Code Analysis

The reason this happens is because for the mob cap in jungle and bamboo jungle biomes they are counted as monsters instead of creatures

Current Code

net/minecraft/data/worldgen/biome/OverworldBiomes.java

public static Biome jungle() {
      MobSpawnSettings.Builder mobspawnsettings$builder = new MobSpawnSettings.Builder();
      BiomeDefaultFeatures.baseJungleSpawns(mobspawnsettings$builder);
      mobspawnsettings$builder.addSpawn(MobCategory.CREATURE, new MobSpawnSettings.SpawnerData(EntityType.PARROT, 40, 1, 2)).addSpawn(MobCategory.MONSTER, new MobSpawnSettings.SpawnerData(EntityType.OCELOT, 2, 1, 3)).addSpawn(MobCategory.CREATURE, new MobSpawnSettings.SpawnerData(EntityType.PANDA, 1, 1, 2));
      return baseJungle(0.9F, false, false, true, mobspawnsettings$builder);
   }

   public static Biome bambooJungle() {
      MobSpawnSettings.Builder mobspawnsettings$builder = new MobSpawnSettings.Builder();
      BiomeDefaultFeatures.baseJungleSpawns(mobspawnsettings$builder);
      mobspawnsettings$builder.addSpawn(MobCategory.CREATURE, new MobSpawnSettings.SpawnerData(EntityType.PARROT, 40, 1, 2)).addSpawn(MobCategory.CREATURE, new MobSpawnSettings.SpawnerData(EntityType.PANDA, 80, 1, 2)).addSpawn(MobCategory.MONSTER, new MobSpawnSettings.SpawnerData(EntityType.OCELOT, 2, 1, 1));
      return baseJungle(0.9F, true, false, true, mobspawnsettings$builder);
   }

Fixed Code

net/minecraft/data/worldgen/biome/OverworldBiomes.java

public static Biome jungle() {
      MobSpawnSettings.Builder mobspawnsettings$builder = new MobSpawnSettings.Builder();
      BiomeDefaultFeatures.baseJungleSpawns(mobspawnsettings$builder);
      //Setting the MobCategory to Creature for Ocelot fixes MC-1788
      mobspawnsettings$builder.addSpawn(MobCategory.CREATURE, new MobSpawnSettings.SpawnerData(EntityType.PARROT, 40, 1, 2)).addSpawn(MobCategory.CREATURE, new MobSpawnSettings.SpawnerData(EntityType.OCELOT, 2, 1, 3)).addSpawn(MobCategory.CREATURE, new MobSpawnSettings.SpawnerData(EntityType.PANDA, 1, 1, 2));
      return baseJungle(0.9F, false, false, true, mobspawnsettings$builder);
   }

   public static Biome bambooJungle() {
      MobSpawnSettings.Builder mobspawnsettings$builder = new MobSpawnSettings.Builder();
      BiomeDefaultFeatures.baseJungleSpawns(mobspawnsettings$builder);
      //Setting the MobCategory to Creature for Ocelot fixes MC-1788
      mobspawnsettings$builder.addSpawn(MobCategory.CREATURE, new MobSpawnSettings.SpawnerData(EntityType.PARROT, 40, 1, 2)).addSpawn(MobCategory.CREATURE, new MobSpawnSettings.SpawnerData(EntityType.PANDA, 80, 1, 2)).addSpawn(MobCategory.CREATURE, new MobSpawnSettings.SpawnerData(EntityType.OCELOT, 2, 1, 1));
      return baseJungle(0.9F, true, false, true, mobspawnsettings$builder);
   }