WakeupAfterClose.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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 */

/* @test
 * @bug 6524172
 * @summary Invoking wakeup on closed Selector can throw NPE if close resets interrupt status
 */

import java.io.IOException;
import java.nio.channels.ClosedSelectorException;
import java.nio.channels.Selector;

public class WakeupAfterClose {

    public static void main(String[] args) throws Exception {
        final Selector sel = Selector.open();

        Runnable r = new Runnable() {
            public void run() {
                try {
                    sel.select();
                } catch (IOException x) {
                    x.printStackTrace();
                } catch (ClosedSelectorException y) {
                    System.err.println
                        ("Caught expected ClosedSelectorException");
                }
            }
        };

        // start thread to block in Selector
        Thread t = new Thread(r);
        t.start();

        // give thread time to start
        Thread.sleep(1000);

        // interrupt, close, and wakeup is the magic sequence to provoke the NPE
        t.interrupt();
        sel.close();
        sel.wakeup();
    }
}