code: private List<InMemoryMappingFile> copyInMemoryMappingFiles(List<InMemoryMappingFile> copyIMMF) {
          List<InMemoryMappingFile> immf = new ArrayList<InMemoryMappingFile>();
          for (InMemoryMappingFile file : copyIMMF) {
              immf.add(new InMemoryMappingFile(file.getMappingFile()));
          }
          return immf;
      }
docs: Private method that takes a list of InMemoryMappingFiles and copies them by assigning a new
  id while sharing the same underlying byte array. This method avoids unnecessarily create
  identical byte arrays. Once all references to a byte array are deleted, the garbage
  collector will cleanup the byte array.