1/* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18package java.lang; 19 20import java.lang.reflect.Method; 21 22/** 23 * Placeholder class for the Java keyword {@code void}. 24 * 25 * @since 1.1 26 */ 27public final class Void extends Object { 28 29 /** 30 * The {@link Class} object that represents the primitive type {@code void}. 31 */ 32 public static final Class<Void> TYPE = lookupType(); 33 34 // Note: This can't be set to "void.class", since *that* is 35 // defined to be "java.lang.Void.TYPE"; 36 37 @SuppressWarnings("unchecked") 38 private static Class<Void> lookupType() { 39 Class<?> voidType = null; 40 try { 41 Method method = Runnable.class.getMethod("run", new Class[0]); 42 voidType = method.getReturnType(); 43 } catch (Exception e) { 44 throw new RuntimeException(e); 45 } 46 return (Class<Void>) voidType; 47 } 48 49 private Void() { 50 } 51} 52