Here you can find the source of callableListCreator()
public static <T> Callable<List<T>> callableListCreator()
//package com.java2s; /**// w ww. j a va 2s. c om * Copyright 2016 Netflix, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ import java.util.ArrayList; import java.util.List; import java.util.concurrent.Callable; public class Main { public static <T> Callable<List<T>> callableListCreator() { return new Callable<List<T>>() { @Override public List<T> call() { return new ArrayList<T>(); } }; } }