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