jdk-24/test/jdk/com/sun/jdi/DebuggeeWrapper.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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import java.lang.reflect.InvocationTargetException;
import java.util.concurrent.ThreadFactory;

public class DebuggeeWrapper {

    public static String PROPERTY_NAME = "main.wrapper";

    private static final String OLD_MAIN_THREAD_NAME = "old-m-a-i-n";

    private static ThreadFactory threadFactory = r -> new Thread(r);

    private static final String wrapperName = System.getProperty(PROPERTY_NAME);

    public static String getWrapperName() {
        return wrapperName;
    }

    public static boolean isVirtual() {
        return "Virtual".equals(wrapperName);
    }

    public static Thread newThread(Runnable task) {
        return threadFactory.newThread(task);
    }

    public static Thread newThread(Runnable task, String name) {
        Thread t = newThread(task);
        t.setName(name);
        return t;
    }

    public static void main(String[] args) throws Throwable {
        String className = args[0];
        String[] classArgs = new String[args.length - 1];
        System.arraycopy(args, 1, classArgs, 0, args.length - 1);
        Class c = Class.forName(className);
        java.lang.reflect.Method mainMethod = c.getMethod("main", new Class[] { String[].class });
        mainMethod.setAccessible(true);

        if (isVirtual()) {
            threadFactory = Thread.ofVirtual().factory();
            MainThreadGroup tg = new MainThreadGroup();
            Thread vthread = Thread.ofVirtual().unstarted(() -> {
                try {
                    mainMethod.invoke(null, new Object[] { classArgs });
                } catch (InvocationTargetException e) {
                    tg.uncaughtThrowable = e.getCause();
                } catch (Throwable error) {
                    tg.uncaughtThrowable = error;
                }
            });
            Thread.currentThread().setName(OLD_MAIN_THREAD_NAME);
            vthread.setName("main");
            vthread.start();
            vthread.join();
            if (tg.uncaughtThrowable != null) {
                // Note we cant just rethrow tg.uncaughtThrowable because there are tests
                // that track ExceptionEvents, and they will complain about the extra
                // exception. So instead mimic what happens when the main thread exits
                // with an exception.
                System.out.println("Uncaught Exception: " + tg.uncaughtThrowable);
                tg.uncaughtThrowable.printStackTrace(System.out);
                System.exit(1);
            }
        } else if (getWrapperName().equals("Kernel")) {
            MainThreadGroup tg = new MainThreadGroup();
            Thread t = new Thread(tg, () -> {
                try {
                    mainMethod.invoke(null, new Object[] { classArgs });
                } catch (InvocationTargetException e) {
                    tg.uncaughtThrowable = e.getCause();
                } catch (Throwable error) {
                    tg.uncaughtThrowable = error;
                }
            });
            t.start();
            t.join();
            if (tg.uncaughtThrowable != null) {
                throw new RuntimeException(tg.uncaughtThrowable);
            }
        } else {
            mainMethod.invoke(null, new Object[] { classArgs });
        }
    }

    static class MainThreadGroup extends ThreadGroup {
        MainThreadGroup() {
            super("MainThreadGroup");
        }

        public void uncaughtException(Thread t, Throwable e) {
            if (e instanceof ThreadDeath) {
                return;
            }
            e.printStackTrace(System.err);
            uncaughtThrowable = e;
        }
        Throwable uncaughtThrowable = null;
    }
}