@Override
  public List<Path> getClassFiles() throws IOException {
    // TODO: Consolidate with createJibContainerBuilder
    FileCollection classesOutputDirectories =
        getMainSourceSet().getOutput().getClassesDirs().filter(File::exists);
    List<Path> classFiles = new ArrayList<>();
    for (File classesOutputDirectory : classesOutputDirectories) {
      classFiles.addAll(new DirectoryWalker(classesOutputDirectory.toPath()).walk());
    }
    return classFiles;
  }
Generate an instance for a gradle project.

@param project a gradle project
@param logger a gradle logging instance to use for logging during the build
@param tempDirectoryProvider for scratch space during the build
@param configurationName the configuration of which the dependencies should be packed into the
    container
@return a GradleProjectProperties instance to use in a jib build
jib-gradle-plugin/src/main/java/com/google/cloud/tools/jib/gradle/GradleProjectProperties.java