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Java example source code file (Version.java)

This example Java source code file (Version.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

charsequence, numberformatexception, runtimeexception, string, stringbuilder, unmatched, versioninfo

The Version.java Java example source code

/*
 * Copyright (c) 2010, 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.
 *
 * 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 6994413
 * @summary Check the JDK and JVM version returned by sun.misc.Version
 *          matches the versions defined in the system properties
 * @compile -XDignore.symbol.file Version.java
 * @run main Version
 */

import static sun.misc.Version.*;
public class Version {

    public static void main(String[] args) throws Exception {
        VersionInfo jdk = newVersionInfo(System.getProperty("java.runtime.version"));
        VersionInfo v1 = new VersionInfo(jdkMajorVersion(),
                                         jdkMinorVersion(),
                                         jdkMicroVersion(),
                                         jdkUpdateVersion(),
                                         jdkSpecialVersion(),
                                         jdkBuildNumber());
        System.out.println("JDK version = " + jdk + "  " + v1);
        if (!jdk.equals(v1)) {
            throw new RuntimeException("Unmatched version: " + jdk + " vs " + v1);
        }
        VersionInfo jvm = newVersionInfo(System.getProperty("java.vm.version"));
        VersionInfo v2 = new VersionInfo(jvmMajorVersion(),
                                         jvmMinorVersion(),
                                         jvmMicroVersion(),
                                         jvmUpdateVersion(),
                                         jvmSpecialVersion(),
                                         jvmBuildNumber());
        System.out.println("JVM version = " + jvm + " " + v2);
        if (!jvm.equals(v2)) {
            throw new RuntimeException("Unmatched version: " + jvm + " vs " + v2);
        }
    }

    static class VersionInfo {
        final int major;
        final int minor;
        final int micro;
        final int update;
        final String special;
        final int build;
        VersionInfo(int major, int minor, int micro,
                    int update, String special, int build) {
            this.major = major;
            this.minor = minor;
            this.micro = micro;
            this.update = update;
            this.special = special;
            this.build = build;
        }

        public boolean equals(VersionInfo v) {
            return (this.major == v.major && this.minor == v.minor &&
                    this.micro == v.micro && this.update == v.update &&
                    this.special.equals(v.special) && this.build == v.build);
        }

        public String toString() {
            StringBuilder sb = new StringBuilder();
            sb.append(major + "." + minor + "." + micro);
            if (update > 0) {
                sb.append("_" + update);
            }

            if (!special.isEmpty()) {
                sb.append(special);
            }
            sb.append("-b" + build);
            return sb.toString();
        }
    }

    private static VersionInfo newVersionInfo(String version) throws Exception {
        // valid format of the version string is:
        // n.n.n[_uu[c]][-<identifer>]-bxx
        int major = 0;
        int minor = 0;
        int micro = 0;
        int update = 0;
        String special = "";
        int build = 0;
        CharSequence cs = version;
        if (cs.length() >= 5) {
            if (Character.isDigit(cs.charAt(0)) && cs.charAt(1) == '.' &&
                Character.isDigit(cs.charAt(2)) && cs.charAt(3) == '.' &&
                Character.isDigit(cs.charAt(4))) {
                major = Character.digit(cs.charAt(0), 10);
                minor = Character.digit(cs.charAt(2), 10);
                micro = Character.digit(cs.charAt(4), 10);
                cs = cs.subSequence(5, cs.length());
            } else if (Character.isDigit(cs.charAt(0)) &&
                       Character.isDigit(cs.charAt(1)) && cs.charAt(2) == '.' &&
                       Character.isDigit(cs.charAt(3))) {
                // HSX has nn.n (major.minor) version
                major = Integer.valueOf(version.substring(0, 2)).intValue();
                minor = Character.digit(cs.charAt(3), 10);
                cs = cs.subSequence(4, cs.length());
            }
            if (cs.charAt(0) == '_' && cs.length() >= 3 &&
                Character.isDigit(cs.charAt(1)) &&
                Character.isDigit(cs.charAt(2))) {
                int nextChar = 3;
                String uu = cs.subSequence(1, 3).toString();
                update = Integer.valueOf(uu).intValue();
                if (cs.length() >= 4) {
                    char c = cs.charAt(3);
                    if (c >= 'a' && c <= 'z') {
                        special = Character.toString(c);
                        nextChar++;
                    }
                }
                cs = cs.subSequence(nextChar, cs.length());
            }
            if (cs.charAt(0) == '-') {
                // skip the first character
                // valid format: <identifier>-bxx or bxx
                // non-product VM will have -debug|-release appended
                cs = cs.subSequence(1, cs.length());
                String[] res = cs.toString().split("-");
                for (int i = res.length - 1; i >= 0; i--) {
                    String s = res[i];
                    if (s.charAt(0) == 'b') {
                        try {
                            build = Integer.parseInt(s.substring(1, s.length()));
                            break;
                        } catch (NumberFormatException nfe) {
                            // ignore
                        }
                    }
                }
            }
        }
        VersionInfo vi = new VersionInfo(major, minor, micro, update, special, build);
        System.out.printf("newVersionInfo: input=%s output=%s\n", version, vi);
        return vi;
    }
}

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