Program: 37903
Project: 37903
Buggy source:
@SubscribeEvent public void harvestBlock(HarvestDropsEvent event){
  if (replacements != null) {
    if (event.block != null) {
      ItemStack oreStack=new ItemStack(event.block,1,event.blockMetadata);
      if (oreStack.getItem() != null) {
        int[] oreIDs=OreDictionary.getOreIDs(oreStack);
        int oreID;
        if (oreIDs.length > 0) {
          for (int i=0; i < oreIDs.length; i++) {
            oreID=oreIDs[i];
            if (oreID > -1) {
              String oreName=OreDictionary.getOreName(oreID);
              if (oreName != null && replacements.containsKey(oreName)) {
                String replacementName=replacements.get(oreName).getString();
                List<String> exclusionNames=Arrays.asList(exclusions.get(oreName).getStringList());
                UniqueIdentifier ore=GameRegistry.findUniqueIdentifierFor(oreStack.getItem());
                if (ore == null) {
                  return;
                }
                if (exclusionNames.contains(ore.modId + "String_Node_Str" + ore.name)) {
                  return;
                }
                ItemStack replacementStack=null;
                for (                ItemStack i1 : OreDictionary.getOres(oreID)) {
                  UniqueIdentifier item=GameRegistry.findUniqueIdentifierFor(i1.getItem());
                  if (item != null && !exclusionNames.contains(item.modId + "String_Node_Str" + item.name) && item.modId.contains(replacementName)) {
                    replacementStack=i1.copy();
                    break;
                  }
                }
                if (replacementStack != null) {
                  for (int i1=0; i1 < event.drops.size(); i1++) {
                    if (event.drops.get(i1) != null && event.drops.get(i1).isItemEqual(oreStack)) {
                      event.drops.set(i1,replacementStack);
                    }
                  }
                }
              }
            }
          }
        }
      }
 else {
        logger.warn("String_Node_Str");
      }
    }
  }
}

Fixed version (ground truth):
@SubscribeEvent public void harvestBlock(HarvestDropsEvent event){
  if (replacements != null) {
    if (event.block != null) {
      ItemStack oreStack=new ItemStack(event.block,1,event.blockMetadata);
      if (oreStack.getItem() != null) {
        int[] oreIDs=OreDictionary.getOreIDs(oreStack);
        int oreID;
        if (oreIDs.length > 0) {
          for (int i=0; i < oreIDs.length; i++) {
            oreID=oreIDs[i];
            if (oreID > -1) {
              String oreName=OreDictionary.getOreName(oreID);
              if (oreName != null && replacements.containsKey(oreName)) {
                String replacementName=replacements.get(oreName).getString();
                Property exclusionDirty=exclusions.get(oreName);
                List<String> exclusionNames=null;
                if (exclusionDirty != null) {
                  exclusionNames=Arrays.asList(exclusionDirty.getStringList());
                }
 else {
                  exclusionNames=new ArrayList<String>();
                }
                UniqueIdentifier ore=GameRegistry.findUniqueIdentifierFor(oreStack.getItem());
                if (ore == null) {
                  return;
                }
                if (exclusionNames.contains(ore.modId + "String_Node_Str" + ore.name)) {
                  return;
                }
                ItemStack replacementStack=null;
                for (                ItemStack i1 : OreDictionary.getOres(oreID)) {
                  UniqueIdentifier item=GameRegistry.findUniqueIdentifierFor(i1.getItem());
                  if (item != null && !exclusionNames.contains(item.modId + "String_Node_Str" + item.name) && item.modId.contains(replacementName)) {
                    replacementStack=i1.copy();
                    break;
                  }
                }
                if (replacementStack != null) {
                  for (int i1=0; i1 < event.drops.size(); i1++) {
                    if (event.drops.get(i1) != null && event.drops.get(i1).isItemEqual(oreStack)) {
                      event.drops.set(i1,replacementStack);
                    }
                  }
                }
              }
            }
          }
        }
      }
 else {
        logger.warn("String_Node_Str");
      }
    }
  }
}