private void addFileToLayer(
      Map<LayerType, FileEntriesLayer.Builder> layerBuilders,
      LayerType layerType,
      Path sourceFile,
      AbsoluteUnixPath pathInContainer) {
    if (!layerBuilders.containsKey(layerType)) {
      layerBuilders.put(layerType, FileEntriesLayer.builder());
    }
    Instant modificationTime = modificationTimeProvider.get(sourceFile, pathInContainer);
    layerBuilders.get(layerType).addEntry(sourceFile, pathInContainer, modificationTime);
  }
Returns a new {@link JibContainerBuilder} using the parameters specified on the {@link
JavaContainerBuilder}.

@return a new {@link JibContainerBuilder} using the parameters specified on the {@link
    JavaContainerBuilder}
@throws IOException if building the {@link JibContainerBuilder} fails.
jib-core/src/main/java/com/google/cloud/tools/jib/api/JavaContainerBuilder.java