jdk/test/java/util/Random/NextIntPowerOfTwoMod.java

/*
 * Copyright 1999 Sun Microsystems, Inc.  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.
 *
 * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

/**
 * @test
 * @bug 4187412
 * @summary The FCS release of 1.2 did not special case the Random.nextInt
 *          calculation for a power of two modulus, as mandated by the spec.
 */

import java.util.Random;

public class NextIntPowerOfTwoMod {
    public static void main(String[] args) throws Exception {
        Random r = new Random(69);
        int total = 0;
        for (int i=0; i<1000; i++)
            total += r.nextInt(16);
        if (total != 7639)
            throw new RuntimeException("Not using correct algorithm.");
    }
}