test/jdk/java/net/InetAddress/GetLoopbackAddress.java

/*
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 * 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.
 *
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 * questions.
 */

/**
 * @test
 * @bug 6376404 8201545
 * @summary InetAddress needs a getLoopbackAddress
 */
import java.net.*;

public class GetLoopbackAddress
{
    static InetAddress IPv4Loopback;
    static InetAddress IPv6Loopback;

    static {
        try {
            IPv4Loopback = InetAddress.getByAddress(
                new byte[] {0x7F,0x00,0x00,0x01});

            IPv6Loopback = InetAddress.getByAddress(
                new byte[] {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01});
        } catch (UnknownHostException e) {
        }
    }

    public static void main(String[] args) throws Exception {
        InetAddress addr = InetAddress.getLoopbackAddress();

        if (!(addr.equals(IPv4Loopback) || addr.equals(IPv6Loopback))) {
            throw new RuntimeException("Failed: getLoopbackAddress" +
                 " not returning a valid loopback address");
        }

        InetAddress addr2 = InetAddress.getLoopbackAddress();

        if (addr != addr2) {
            throw new RuntimeException("Failed: getLoopbackAddress" +
                " should return a reference to the same InetAddress loopback instance.");
        }

        InetAddress addrFromNullHost = InetAddress.getByName(null);
        if (!addrFromNullHost.isLoopbackAddress()) {
            throw new RuntimeException("getByName(null) did not return a" +
            " loopback address, but " + addrFromNullHost);
        }
        InetAddress addrFromEmptyHost = InetAddress.getByName("");
        if (!addrFromEmptyHost.isLoopbackAddress()) {
            throw new RuntimeException("getByName with a host of length == 0," +
                " did not return a loopback address, but " + addrFromEmptyHost);
        }

        InetAddress[] addrsByNull = InetAddress.getAllByName(null);
        if (!addrsByNull[0].isLoopbackAddress()) {
            throw new RuntimeException("getAllByName(null) did not return" +
            " a loopback address, but " + addrsByNull[0]);
        }
        InetAddress[] addrsByEmpty = InetAddress.getAllByName("");
        if (!addrsByEmpty[0].isLoopbackAddress()) {
            throw new RuntimeException("getAllByName with a host of length" +
            " == 0, did not return a loopback address, but " + addrsByEmpty[0]);
        }
    }
}