#vulnerable code 
                              private File copyToMergedCodebase(String filename, File destFile) {
    FileSystem fs = Injector.INSTANCE.fileSystem();
    File mergedFile = mergedCodebase.getFile(filename);
    try {
      fs.makeDirsForFile(mergedFile);
      fs.copyFile(destFile, mergedFile);
      return mergedFile;
    } catch (IOException e) {
      throw new MoeProblem(e.getMessage());
    }
  } 
                            #location 5 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                              private File copyToMergedCodebase(String filename, File destFile) {
    File mergedFile = mergedCodebase.getFile(filename);
    try {
      filesystem.makeDirsForFile(mergedFile);
      filesystem.copyFile(destFile, mergedFile);
      return mergedFile;
    } catch (IOException e) {
      throw new MoeProblem(e.getMessage());
    }
  }