ojluni/src/main/java/java/lang/Void.java

/*
 * Copyright (C) 2014 The Android Open Source Project
 * Copyright (c) 1996, 2011, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.lang;

import java.lang.reflect.Method;
import libcore.util.EmptyArray;

/**
 * The {@code Void} class is an uninstantiable placeholder class to hold a
 * reference to the {@code Class} object representing the Java keyword
 * void.
 *
 * @author  unascribed
 * @since   JDK1.1
 */
public final
class Void {

    /**
     * The {@code Class} object representing the pseudo-type corresponding to
     * the keyword {@code void}.
     */
    public static final Class<Void> TYPE = lookupType();

    // Android-changed: Upstream code would use reflection to establish the value of "void.class".
    // ART makes a native call instead because the reflection approach could lead to initialization
    // of TYPE with the current, i.e. uninitialized, value of TYPE due to other Android changes.
    @dalvik.annotation.optimization.FastNative
    private static native Class<Void> lookupType();
    /*
    @SuppressWarnings("unchecked")
    private static Class<Void> lookupType() {
        try {
            Method method = Runnable.class.getMethod("run", EmptyArray.CLASS);
            return (Class<Void>) method.getReturnType();
        } catch (Exception e) {
            throw new AssertionError(e);
        }
    }
    */

    /*
     * The Void class cannot be instantiated.
     */
    private Void() {}
}