/*

 * Copyright (c) 2004, 2008, 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.

 *

 * 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.

 */

/**

 * @test

 * @bug 4989690 6259855 6706299

 * @summary Check that version-related system property invariants hold.

 * @author Martin Buchholz

 */

import java.io.*;

import java.net.URLClassLoader;

import java.net.URL;

public class Versions {

    static String getProperty(String prop) throws Exception {

        String value = System.getProperty(prop);

        if (value == null)

            throw new Exception("No such system property: " + prop);

        System.out.printf("%s=%s%n", prop, value);

        return value;

    }

    static ClassLoader cl;

    static void checkClassVersion(int major, int minor, boolean expectSupported)

        throws Exception

    {

        final String className  = "ClassVersionTest";

        final String classFile  = className + ".class";

        // We create an invalid class file, (only magic and version info),

        // but the version info must be checked before the body.

        final DataOutputStream dos =

            new DataOutputStream(new FileOutputStream(classFile));

        dos.writeLong((0xCafeBabel << 32) + (minor << 16) + major);

        dos.close();

        boolean supported = true;

        try {

            Class.forName(className, false, cl);

        } catch (UnsupportedClassVersionError e) {

            supported = false;

        } catch (Throwable t) {

            // We expect an Exception indicating invalid class file

        }

        new File(classFile).delete();

        if (supported != expectSupported)

            throw new Exception("Forgot to update java.class.version?");

    }

    public static void main(String [] args) throws Exception {

        String classVersion   = getProperty("java.class.version");

        String javaVersion    = getProperty("java.version");

        String VMVersion      = getProperty("java.vm.version");

        String runtimeVersion = getProperty("java.runtime.version");

        String specVersion    = getProperty("java.specification.version");

        if (! (javaVersion.startsWith(specVersion) &&

               runtimeVersion.startsWith(specVersion)))

            throw new Exception("Invalid version-related system properties");

        //----------------------------------------------------------------

        // Check that java.class.version is correct.

        // Injecting a larger major or minor version number into a

        // .class file should result in UnsupportedClassVersionError.

        //----------------------------------------------------------------

        String[] versions = classVersion.split("\\.");

        int majorVersion = Integer.parseInt(versions[0]);

        int minorVersion = Integer.parseInt(versions[1]);

        System.out.printf("majorVersion=%s%n",majorVersion);

        System.out.printf("minorVersion=%s%n",minorVersion);

        // Look in ".", and *not* in CLASSPATH

        cl = new URLClassLoader(new URL[]{new File("./").toURL()}, null);

        checkClassVersion(majorVersion    , minorVersion    , true );

        checkClassVersion(majorVersion + 1, minorVersion    , false);

        checkClassVersion(majorVersion    , minorVersion + 1, false);

    }

}