make/jdk/src/classes/build/tools/classlist/HelloClasslist.java

/*
 * Copyright (c) 2016, 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.
 */

/**
 * This application is meant to be run to create a classlist file representing
 * common use.
 *
 * The classlist is produced by adding -XX:DumpLoadedClassList=classlist
 */
package build.tools.classlist;

import java.net.InetAddress;
import java.nio.file.FileSystems;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.util.stream.Stream;
import java.util.logging.*;
import java.util.Arrays;
import java.util.Date;
import java.util.List;
import java.util.Locale;
import java.text.DateFormat;

import static java.util.stream.Collectors.*;

/**
 * This class is used to generate a classlist during build. Intent
 * is to touch a reasonable amount of JDK classes that are commonly
 * loaded and used early.
 */
public class HelloClasslist {

    private static final Logger LOGGER = Logger.getLogger("Hello");

    public static void main(String ... args) {

        FileSystems.getDefault();

        List<String> strings = Arrays.asList("Hello", "World!", "From: ",
              InetAddress.getLoopbackAddress().toString());

        String helloWorld = strings.parallelStream()
              .map(s -> s.toLowerCase(Locale.ROOT))
              .collect(joining(","));

        Stream.of(helloWorld.split(","))
              .forEach(System.out::println);

        String newDate = DateTimeFormatter.ISO_LOCAL_DATE_TIME.format(
                LocalDateTime.now(ZoneId.of("GMT")));

        String oldDate = String.format("%s%n",
                DateFormat.getDateInstance(DateFormat.DEFAULT, Locale.ROOT)
                        .format(new Date()));

        LOGGER.log(Level.INFO, "New Date: " + newDate + " - old: " + oldDate);
    }

}