Program: 188770
Project: 188770
Buggy source:
public void createEvent(List<File> alteredFiles,List<File> newFiles,AIP aip,String newRepresentationID,ModelService model,int state,IndexedPreservationAgent agent,boolean notify) throws PluginException {
  List<String> premisSourceFilesIdentifiers=new ArrayList<String>();
  List<String> premisTargetFilesIdentifiers=new ArrayList<String>();
  String outcome="String_Node_Str";
  StringBuilder stringBuilder=new StringBuilder();
  if (alteredFiles.size() == 0) {
    stringBuilder.append("String_Node_Str");
  }
 else {
    stringBuilder.append("String_Node_Str");
    for (    File file : alteredFiles) {
      stringBuilder.append(file.getId() + "String_Node_Str");
      premisSourceFilesIdentifiers.add(PremisUtils.createPremisFileIdentifier(file));
    }
    for (    File file : newFiles) {
      premisTargetFilesIdentifiers.add(PremisUtils.createPremisFileIdentifier(file));
    }
    stringBuilder.setLength(stringBuilder.length() - 2);
  }
  if (state == 0 || (state == 2 && hasPartialSuccessOnOutcome == false)) {
    outcome="String_Node_Str";
    stringBuilder.setLength(0);
  }
  if (state == 2 && hasPartialSuccessOnOutcome == true) {
    outcome="String_Node_Str";
  }
  try {
    PluginHelper.createPluginEvent(aip.getId(),newRepresentationID,null,model,RodaConstants.PRESERVATION_EVENT_TYPE_MIGRATION,"String_Node_Str",premisSourceFilesIdentifiers,premisTargetFilesIdentifiers,outcome,stringBuilder.toString(),null,agent,notify);
  }
 catch (  IOException|RequestNotValidException|NotFoundException|GenericException|AuthorizationDeniedException|ValidationException|AlreadyExistsException e) {
    throw new PluginException(e.getMessage(),e);
  }
}

Fixed version (ground truth):
public void createEvent(List<File> alteredFiles,List<File> newFiles,AIP aip,String newRepresentationID,ModelService model,int state,IndexedPreservationAgent agent,boolean notify) throws PluginException {
  List<String> premisSourceFilesIdentifiers=new ArrayList<String>();
  List<String> premisTargetFilesIdentifiers=new ArrayList<String>();
  String outcome="String_Node_Str";
  StringBuilder stringBuilder=new StringBuilder();
  if (alteredFiles.size() == 0) {
    stringBuilder.append("String_Node_Str");
  }
 else {
    stringBuilder.append("String_Node_Str");
    for (    File file : alteredFiles) {
      stringBuilder.append(file.getId() + "String_Node_Str");
      premisSourceFilesIdentifiers.add(PremisUtils.createPremisFileIdentifier(file));
    }
    for (    File file : newFiles) {
      premisTargetFilesIdentifiers.add(PremisUtils.createPremisFileIdentifier(file));
    }
    stringBuilder.setLength(stringBuilder.length() - 2);
  }
  if (state == 0 || (state == 2 && hasPartialSuccessOnOutcome() == false)) {
    outcome="String_Node_Str";
    stringBuilder.setLength(0);
  }
  if (state == 2 && hasPartialSuccessOnOutcome() == true) {
    outcome="String_Node_Str";
  }
  try {
    PluginHelper.createPluginEvent(aip.getId(),newRepresentationID,null,model,RodaConstants.PRESERVATION_EVENT_TYPE_MIGRATION,"String_Node_Str",premisSourceFilesIdentifiers,premisTargetFilesIdentifiers,outcome,stringBuilder.toString(),null,agent,notify);
  }
 catch (  IOException|RequestNotValidException|NotFoundException|GenericException|AuthorizationDeniedException|ValidationException|AlreadyExistsException e) {
    throw new PluginException(e.getMessage(),e);
  }
}