Program: 44397
Project: 44397
Buggy source:
public void registerCreatureDeath(CreatureKilledByPlayerEvent event){
  if (shouldClearDefaultDrops) {
    event.getDrops().clear();
    event.setDroppedExp(0);
  }
  if (event.getKiller().getItemInHand().getType().equals(Material.BOW) && !hasBowRewards) {
    plugin.getMessageManager(event.getKiller().getWorld()).sendMessage(plugin.getMessageManager(event.getKiller().getWorld()).noBowRewardMessage,event.getKiller());
    return;
  }
 else   if (ecoEntityUtil.isUnderSeaLevel(event.getKiller()) && !canHuntUnderSeaLevel) {
    plugin.getMessageManager(event.getKiller().getWorld()).sendMessage(plugin.getMessageManager(event.getKiller().getWorld()).noBowRewardMessage,event.getKiller());
    return;
  }
 else   if (ecoEntityUtil.isOwner(event.getKiller(),event.getKilledCreature())) {
    ecoCreature.getEcoLogger().debug("String_Node_Str" + event.getKiller().getName() + "String_Node_Str");
    return;
  }
 else   if (ecoCreature.mobArenaHandler != null && ecoCreature.mobArenaHandler.isPlayerInArena(event.getKiller()) && !hasMobArenaRewards) {
    ecoCreature.getEcoLogger().debug("String_Node_Str" + event.getKiller().getName() + "String_Node_Str");
    return;
  }
 else   if (!hasCreativeModeRewards && event.getKiller().getGameMode() == GameMode.CREATIVE) {
    ecoCreature.getEcoLogger().debug("String_Node_Str" + event.getKiller().getName() + "String_Node_Str");
    return;
  }
 else   if (!canCampSpawner && (campByDistance || campByEntity)) {
    if ((campByEntity && plugin.isSpawnerMob(event.getKilledCreature())) || (campByDistance && (isNearSpawner(event.getKiller()) || isNearSpawner(event.getKilledCreature())))) {
      if (shouldClearCampDrops) {
        event.getDrops().clear();
        event.setDroppedExp(0);
      }
      plugin.getMessageManager(event.getKiller().getWorld()).sendMessage(plugin.getMessageManager(event.getKiller().getWorld()).noCampMessage,event.getKiller());
      ecoCreature.getEcoLogger().debug("String_Node_Str" + event.getKiller().getName() + "String_Node_Str");
      return;
    }
  }
 else   if (!plugin.hasPermission(event.getKiller(),"String_Node_Str" + RewardType.fromEntity(event.getKilledCreature()).getName())) {
    ecoCreature.getEcoLogger().debug("String_Node_Str" + event.getKiller().getName() + "String_Node_Str"+ RewardType.fromEntity(event.getKilledCreature()).getName());
    return;
  }
  ecoReward reward=getRewardFromEntity(event.getKilledCreature());
  if (reward != null) {
    Integer exp=reward.getExpAmount();
    if (exp != null) {
      event.setDroppedExp(exp);
    }
    String weaponName=event.getTamedCreature() != null ? RewardType.fromEntity(event.getTamedCreature()).getName() : Material.getMaterial(event.getKiller().getItemInHand().getTypeId()).name();
    registerReward(event.getKiller(),reward,weaponName);
    try {
      List<ItemStack> rewardDrops=reward.computeDrops();
      if (!rewardDrops.isEmpty()) {
        if (!event.getDrops().isEmpty() && shouldOverrideDrops) {
          event.getDrops().clear();
        }
        event.getDrops().addAll(rewardDrops);
      }
    }
 catch (    IllegalArgumentException e) {
      ecoCreature.getEcoLogger().warning(e.getMessage());
    }
  }
}

Fixed version (ground truth):
public void registerCreatureDeath(CreatureKilledByPlayerEvent event){
  if (shouldClearDefaultDrops) {
    event.getDrops().clear();
    event.setDroppedExp(0);
  }
  if (event.getKiller().getItemInHand().getType().equals(Material.BOW) && !hasBowRewards) {
    plugin.getMessageManager(event.getKiller().getWorld()).sendMessage(plugin.getMessageManager(event.getKiller().getWorld()).noBowRewardMessage,event.getKiller());
    return;
  }
  if (ecoEntityUtil.isUnderSeaLevel(event.getKiller()) && !canHuntUnderSeaLevel) {
    plugin.getMessageManager(event.getKiller().getWorld()).sendMessage(plugin.getMessageManager(event.getKiller().getWorld()).noBowRewardMessage,event.getKiller());
    return;
  }
  if (ecoEntityUtil.isOwner(event.getKiller(),event.getKilledCreature())) {
    ecoCreature.getEcoLogger().debug("String_Node_Str" + event.getKiller().getName() + "String_Node_Str");
    return;
  }
  if (ecoCreature.mobArenaHandler != null && ecoCreature.mobArenaHandler.isPlayerInArena(event.getKiller()) && !hasMobArenaRewards) {
    ecoCreature.getEcoLogger().debug("String_Node_Str" + event.getKiller().getName() + "String_Node_Str");
    return;
  }
  if (!hasCreativeModeRewards && event.getKiller().getGameMode() == GameMode.CREATIVE) {
    ecoCreature.getEcoLogger().debug("String_Node_Str" + event.getKiller().getName() + "String_Node_Str");
    return;
  }
  if (!canCampSpawner && (campByDistance || campByEntity)) {
    if ((campByEntity && plugin.isSpawnerMob(event.getKilledCreature())) || (campByDistance && (isNearSpawner(event.getKiller()) || isNearSpawner(event.getKilledCreature())))) {
      if (shouldClearCampDrops) {
        event.getDrops().clear();
        event.setDroppedExp(0);
      }
      plugin.getMessageManager(event.getKiller().getWorld()).sendMessage(plugin.getMessageManager(event.getKiller().getWorld()).noCampMessage,event.getKiller());
      ecoCreature.getEcoLogger().debug("String_Node_Str" + event.getKiller().getName() + "String_Node_Str");
      return;
    }
  }
  if (!plugin.hasPermission(event.getKiller(),"String_Node_Str" + RewardType.fromEntity(event.getKilledCreature()).getName())) {
    ecoCreature.getEcoLogger().debug("String_Node_Str" + event.getKiller().getName() + "String_Node_Str"+ RewardType.fromEntity(event.getKilledCreature()).getName());
    return;
  }
  ecoReward reward=getRewardFromEntity(event.getKilledCreature());
  if (reward != null) {
    Integer exp=reward.getExpAmount();
    if (exp != null) {
      event.setDroppedExp(exp);
    }
    String weaponName=event.getTamedCreature() != null ? RewardType.fromEntity(event.getTamedCreature()).getName() : Material.getMaterial(event.getKiller().getItemInHand().getTypeId()).name();
    registerReward(event.getKiller(),reward,weaponName);
    try {
      List<ItemStack> rewardDrops=reward.computeDrops();
      if (!rewardDrops.isEmpty()) {
        if (!event.getDrops().isEmpty() && shouldOverrideDrops) {
          event.getDrops().clear();
        }
        event.getDrops().addAll(rewardDrops);
      }
    }
 catch (    IllegalArgumentException e) {
      ecoCreature.getEcoLogger().warning(e.getMessage());
    }
  }
}