JBR-3862 Implement native WatchService on MacOS

The watch service is based on FSEvents API that notifies about file
system changes at a directory level. It is possible to go back to
using the old polling watch service with -Dwatch.service.polling=true.

Features include:
- support for FILE_TREE option (recursive directory watching),
- minimum necessary I/O (no filesystem access more than once
  unless needed),
- one thread ("run loop") per WatchService instance,
- changes are detected by comparing file modification times with
  millisecond precision,
- a directory tree snapshot is taken at the time of WatchKey creation
  and can take a long time (proportional to the number of files).

src/java.base/macosx/classes/sun/nio/fs/BsdFileSystem.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2022, 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
@@ -28,8 +28,6 @@ package sun.nio.fs;
 import java.nio.file.*;
 import java.io.IOException;
 import java.util.*;
-import java.security.AccessController;
-import sun.security.action.GetPropertyAction;
 
 /**
  * Bsd implementation of FileSystem
@@ -45,8 +43,8 @@ class BsdFileSystem extends UnixFileSystem {
     public WatchService newWatchService()
         throws IOException
     {
-        // use polling implementation until we implement a BSD/kqueue one
-        return new PollingWatchService();
+        final boolean usePollingWatchService = Boolean.getBoolean("watch.service.polling");
+        return usePollingWatchService ? new PollingWatchService() : new MacOSXWatchService();
     }
 
     // lazy initialization of the list of supported attribute views

src/java.base/macosx/classes/sun/nio/fs/MacOSXWatchService.java

@@ -0,0 +1,826 @@
+/*
+ * Copyright (c) 2021, 2022, JetBrains s.r.o.. 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.
+ */
+
+package sun.nio.fs;
+
+import sun.util.logging.PlatformLogger;
+
+import jdk.internal.misc.Unsafe;
+
+import java.io.IOException;
+import java.nio.file.ClosedWatchServiceException;
+import java.nio.file.DirectoryIteratorException;
+import java.nio.file.DirectoryStream;
+import java.nio.file.Files;
+import java.nio.file.LinkOption;
+import java.nio.file.NotDirectoryException;
+import java.nio.file.Path;
+import java.nio.file.StandardWatchEventKinds;
+import java.nio.file.WatchEvent;
+import java.nio.file.WatchKey;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.util.ArrayDeque;
+import java.util.EnumSet;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.LinkedHashSet;
+import java.util.LinkedList;
+import java.util.Map;
+import java.util.Queue;
+import java.util.Set;
+import java.util.function.Consumer;
+
+class MacOSXWatchService extends AbstractWatchService {
+    // Controls tracing in the native part of the watcher.
+    private static boolean tracingEnabled = false;
+    private static final PlatformLogger logger = PlatformLogger.getLogger("sun.nio.fs.MacOSXWatchService");
+
+    private final HashMap<Object, MacOSXWatchKey> dirKeyToWatchKey      = new HashMap<>();
+    private final HashMap<Long, MacOSXWatchKey>   eventStreamToWatchKey = new HashMap<>();
+    private final Object                          watchKeysLock         = new Object();
+
+    private final CFRunLoopThread runLoopThread;
+
+    MacOSXWatchService() throws IOException {
+        runLoopThread = new CFRunLoopThread();
+        runLoopThread.setDaemon(true);
+        runLoopThread.start();
+
+        try {
+            // In order to be able to schedule any FSEventStream's, a reference to a run loop is required.
+            runLoopThread.waitForRunLoopRef();
+        } catch (InterruptedException e) {
+            throw new IOException(e);
+        }
+    }
+
+    @Override
+    WatchKey register(Path dir, WatchEvent.Kind<?>[] events, WatchEvent.Modifier... modifiers) throws IOException {
+        checkIsOpen();
+
+        final UnixPath unixDir = (UnixPath)dir;
+        final Object dirKey    = checkPath(unixDir);
+        final EnumSet<FSEventKind>   eventSet    = FSEventKind.setOf(events);
+        final EnumSet<WatchModifier> modifierSet = WatchModifier.setOf(modifiers);
+        synchronized (closeLock()) {
+            checkIsOpen();
+
+            if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                logger.finest("register for " + dir);
+
+            synchronized (watchKeysLock) {
+                MacOSXWatchKey watchKey = dirKeyToWatchKey.get(dirKey);
+                final boolean keyForDirAlreadyExists = (watchKey != null);
+                if (keyForDirAlreadyExists) {
+                    eventStreamToWatchKey.remove(watchKey.getEventStreamRef());
+                    watchKey.disable();
+                    if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                        logger.finest("re-used existing watch key");
+                } else {
+                    watchKey = new MacOSXWatchKey(this, unixDir, dirKey);
+                    dirKeyToWatchKey.put(dirKey, watchKey);
+                    if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                        logger.finest("created a new watch key");
+                }
+                if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                    logger.finest("starting to [re-]populate directory cache with data");
+                watchKey.enable(runLoopThread, eventSet, modifierSet);
+                eventStreamToWatchKey.put(watchKey.getEventStreamRef(), watchKey);
+                watchKeysLock.notify(); // So that run loop gets running again if stopped due to lack of event streams
+                return watchKey;
+            }
+        }
+    }
+
+    /**
+     * Invoked on the CFRunLoopThread by the native code to report directories that need to be re-scanned.
+     */
+    private void callback(final long eventStreamRef, final String[] paths, final long eventFlagsPtr) {
+        synchronized (watchKeysLock) {
+            final MacOSXWatchKey watchKey = eventStreamToWatchKey.get(eventStreamRef);
+            if (watchKey != null) {
+                if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                    logger.finest("Callback fired for '" + watchKey.getRealRootPath() + "'");
+                watchKey.handleEvents(paths, eventFlagsPtr);
+            } else {
+                if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                    logger.finest("Callback fired for watch key that is no longer there");
+            }
+        }
+    }
+
+    void cancel(final MacOSXWatchKey watchKey) {
+        synchronized (watchKeysLock) {
+            dirKeyToWatchKey.remove(watchKey.getRootPathKey());
+            eventStreamToWatchKey.remove(watchKey.getEventStreamRef());
+        }
+    }
+
+    void waitForEventSource() {
+        synchronized (watchKeysLock) {
+            if (isOpen() && eventStreamToWatchKey.isEmpty()) {
+                try {
+                    watchKeysLock.wait();
+                } catch (InterruptedException ignore) {}
+            }
+        }
+    }
+
+    @Override
+    void implClose() {
+        synchronized (watchKeysLock) {
+            eventStreamToWatchKey.clear();
+            dirKeyToWatchKey.forEach((key, watchKey) -> watchKey.invalidate());
+            dirKeyToWatchKey.clear();
+            watchKeysLock.notify(); // Let waitForEventSource() go if it was waiting
+            runLoopThread.runLoopStop(); // Force exit from CFRunLoopRun()
+        }
+    }
+
+    private static void traceLine(final String text) {
+        logger.finest("NATIVE trace: " + text);
+    }
+
+    private class CFRunLoopThread extends Thread {
+        // Native reference to the CFRunLoop object of the watch service run loop.
+        private long runLoopRef;
+
+        public CFRunLoopThread() {
+            super("FileSystemWatcher");
+        }
+
+        synchronized void waitForRunLoopRef() throws InterruptedException {
+            if (runLoopRef == 0)
+                runLoopThread.wait(); // ...for CFRunLoopRef to become available
+        }
+
+        long getRunLoopRef() {
+            return runLoopRef;
+        }
+
+        synchronized void runLoopStop() {
+            if (runLoopRef != 0) {
+                // The run loop may have stuck in CFRunLoopRun() even though all of its input sources
+                // have been removed. Need to terminate it explicitly so that it can run to completion.
+                MacOSXWatchService.CFRunLoopStop(runLoopRef);
+            }
+        }
+
+        @Override
+        public void run() {
+            synchronized (this) {
+                runLoopRef = CFRunLoopGetCurrent();
+                notify();
+            }
+
+            while (isOpen()) {
+                CFRunLoopRun(MacOSXWatchService.this);
+                waitForEventSource();
+            }
+
+            synchronized (this) {
+                runLoopRef = 0; // CFRunLoopRef is no longer usable when the loop has been terminated
+            }
+        }
+    }
+
+    private void checkIsOpen() {
+        if (!isOpen())
+            throw new ClosedWatchServiceException();
+    }
+
+    private Object checkPath(UnixPath dir) throws IOException {
+        if (dir == null)
+            throw new NullPointerException("No path to watch");
+
+        UnixFileAttributes attrs;
+        try {
+            attrs = UnixFileAttributes.get(dir, true);
+        } catch (UnixException x) {
+            throw x.asIOException(dir);
+        }
+
+        if (!attrs.isDirectory())
+            throw new NotDirectoryException(dir.getPathForExceptionMessage());
+
+        final Object fileKey = attrs.fileKey();
+        if (fileKey == null)
+            throw new AssertionError("File keys must be supported");
+
+        return fileKey;
+    }
+
+    private enum FSEventKind {
+        CREATE, MODIFY, DELETE, OVERFLOW;
+
+        public static FSEventKind of(final WatchEvent.Kind<?> watchEventKind) {
+            if (StandardWatchEventKinds.ENTRY_CREATE == watchEventKind) {
+                return CREATE;
+            } else if (StandardWatchEventKinds.ENTRY_MODIFY == watchEventKind) {
+                return MODIFY;
+            } else if (StandardWatchEventKinds.ENTRY_DELETE == watchEventKind) {
+                return DELETE;
+            } else if (StandardWatchEventKinds.OVERFLOW == watchEventKind) {
+                return OVERFLOW;
+            } else {
+                throw new UnsupportedOperationException(watchEventKind.name());
+            }
+        }
+
+        public static EnumSet<FSEventKind> setOf(final WatchEvent.Kind<?>[] events) {
+            final EnumSet<FSEventKind> eventSet = EnumSet.noneOf(FSEventKind.class);
+            for (final WatchEvent.Kind<?> event: events) {
+                if (event == null) {
+                    throw new NullPointerException("An element in event set is 'null'");
+                } else if (event == StandardWatchEventKinds.OVERFLOW) {
+                    continue;
+                }
+
+                eventSet.add(FSEventKind.of(event));
+            }
+
+            if (eventSet.isEmpty())
+                throw new IllegalArgumentException("No events to register");
+
+            return eventSet;
+        }
+
+    }
+
+    private enum WatchModifier {
+        FILE_TREE, SENSITIVITY_HIGH, SENSITIVITY_MEDIUM, SENSITIVITY_LOW;
+
+        public static WatchModifier of(final WatchEvent.Modifier watchEventModifier) {
+            if (ExtendedOptions.FILE_TREE.matches(watchEventModifier)) {
+                return FILE_TREE;
+            } if (ExtendedOptions.SENSITIVITY_HIGH.matches(watchEventModifier)) {
+                return SENSITIVITY_HIGH;
+            } if (ExtendedOptions.SENSITIVITY_MEDIUM.matches(watchEventModifier)) {
+                return SENSITIVITY_MEDIUM;
+            } if (ExtendedOptions.SENSITIVITY_LOW.matches(watchEventModifier)) {
+                return SENSITIVITY_LOW;
+            } else {
+                throw new UnsupportedOperationException(watchEventModifier.name());
+            }
+        }
+
+        public static EnumSet<WatchModifier> setOf(final WatchEvent.Modifier[] modifiers) {
+            final EnumSet<WatchModifier> modifierSet = EnumSet.noneOf(WatchModifier.class);
+            for (final WatchEvent.Modifier modifier : modifiers) {
+                if (modifier == null)
+                    throw new NullPointerException("An element in modifier set is 'null'");
+
+                modifierSet.add(WatchModifier.of(modifier));
+            }
+
+            return modifierSet;
+        }
+
+        public static double sensitivityOf(final EnumSet<WatchModifier> modifiers) {
+            if (modifiers.contains(SENSITIVITY_HIGH)) {
+                return 0.1;
+            } else if (modifiers.contains(SENSITIVITY_LOW)) {
+                return 1;
+            } else {
+                return 0.5; // aka SENSITIVITY_MEDIUM
+            }
+        }
+    }
+
+    private static class MacOSXWatchKey extends AbstractWatchKey {
+        private static final Unsafe unsafe = Unsafe.getUnsafe();
+
+        private static final long kFSEventStreamEventFlagMustScanSubDirs = 0x00000001;
+        private static final long kFSEventStreamEventFlagRootChanged     = 0x00000020;
+
+        private final static Path relativeRootPath = Path.of("");
+
+        // Full path to this key's watch root directory.
+        private final Path   realRootPath;
+        private final int    realRootPathLength;
+        private final Object rootPathKey;
+
+        // Kinds of events to be reported.
+        private EnumSet<FSEventKind> eventsToWatch;
+
+        // Should events in directories below realRootPath reported?
+        private boolean watchFileTree;
+
+        // Native FSEventStreamRef as returned by FSEventStreamCreate().
+        private long         eventStreamRef;
+        private final Object eventStreamRefLock = new Object();
+
+        private final DirectoryTreeSnapshot directoryTreeSnapshot = new DirectoryTreeSnapshot();
+
+        MacOSXWatchKey(final MacOSXWatchService watchService, final UnixPath dir, final Object rootPathKey) throws IOException {
+            super(dir, watchService);
+            this.realRootPath       = dir.toRealPath().normalize();
+            this.realRootPathLength = realRootPath.toString().length() + 1;
+            this.rootPathKey        = rootPathKey;
+        }
+
+        synchronized void enable(final CFRunLoopThread runLoopThread,
+                                 final EnumSet<FSEventKind> eventsToWatch,
+                                 final EnumSet<WatchModifier> modifierSet) throws IOException {
+            assert(!isValid());
+
+            this.eventsToWatch = eventsToWatch;
+            this.watchFileTree = modifierSet.contains(WatchModifier.FILE_TREE);
+
+            directoryTreeSnapshot.build();
+
+            synchronized (eventStreamRefLock) {
+                final int kFSEventStreamCreateFlagWatchRoot  = 0x00000004;
+                eventStreamRef = MacOSXWatchService.eventStreamCreate(
+                        realRootPath.toString(),
+                        WatchModifier.sensitivityOf(modifierSet),
+                        kFSEventStreamCreateFlagWatchRoot);
+
+                if (eventStreamRef == 0)
+                    throw new IOException("Unable to create FSEventStream");
+
+                MacOSXWatchService.eventStreamSchedule(eventStreamRef, runLoopThread.getRunLoopRef());
+            }
+        }
+
+        synchronized void disable() {
+            invalidate();
+            directoryTreeSnapshot.reset();
+        }
+
+        synchronized void handleEvents(final String[] paths, long eventFlagsPtr) {
+            if (paths == null) {
+                reportOverflow(null);
+                return;
+            }
+
+            if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                logger.finest("handleEvents(): will handle " + paths.length + " events");
+
+            final Set<Path> dirsToScan = new LinkedHashSet<>(paths.length);
+            final Set<Path> dirsToScanRecursively = new LinkedHashSet<>();
+            collectDirsToScan(paths, eventFlagsPtr, dirsToScan, dirsToScanRecursively);
+
+            for (final Path recurseDir : dirsToScanRecursively) {
+                if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                    logger.finest("handleEvents(): scanning directory recursively " + recurseDir);
+                dirsToScan.removeIf(dir -> dir.startsWith(recurseDir));
+                assert(watchFileTree);
+                directoryTreeSnapshot.update(recurseDir, true);
+            }
+
+            for (final Path dir : dirsToScan) {
+                if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                    logger.finest("handleEvents(): scanning directory " + dir);
+                directoryTreeSnapshot.update(dir, false);
+            }
+        }
+
+        private Path toRelativePath(final String absPath) {
+            return   (absPath.length() > realRootPathLength)
+                    ? Path.of(absPath.substring(realRootPathLength))
+                    : relativeRootPath;
+        }
+
+        private void collectDirsToScan(final String[] paths, long eventFlagsPtr,
+                                       final Set<Path> dirsToScan,
+                                       final Set<Path> dirsToScanRecursively) {
+            for (final String absPath : paths) {
+                if (absPath == null) {
+                    reportOverflow(null);
+                    continue;
+                }
+
+                Path path = toRelativePath(absPath);
+
+                if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                    logger.finest("handleEvents(): event path name " + path);
+
+                if (!watchFileTree && !relativeRootPath.equals(path)) {
+                    if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                        logger.finest("handleEvents(): skipping event for a nested directory");
+                    continue;
+                }
+
+                final int flags = unsafe.getInt(eventFlagsPtr);
+                if ((flags & kFSEventStreamEventFlagRootChanged) != 0) {
+                    if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                        logger.finest("handleEvents(): watch root changed, path=" + path);
+                    cancel();
+                    signal();
+                    break;
+                } else if ((flags & kFSEventStreamEventFlagMustScanSubDirs) != 0 && watchFileTree) {
+                    dirsToScanRecursively.add(path);
+                } else {
+                    dirsToScan.add(path);
+                }
+
+                final long SIZEOF_FS_EVENT_STREAM_EVENT_FLAGS = 4L; // FSEventStreamEventFlags is UInt32
+                eventFlagsPtr += SIZEOF_FS_EVENT_STREAM_EVENT_FLAGS;
+            }
+        }
+
+        /**
+         * Represents a snapshot of a directory tree.
+         * The snapshot includes subdirectories iff <code>watchFileTree</code> is <code>true</code>.
+         */
+        private class DirectoryTreeSnapshot {
+            private final HashMap<Path, DirectorySnapshot> snapshots;
+
+            DirectoryTreeSnapshot() {
+                this.snapshots = new HashMap<>(watchFileTree ? 256 : 1);
+            }
+
+            void build() throws IOException {
+                final Queue<Path> pathToDo = new ArrayDeque<>();
+                pathToDo.offer(relativeRootPath);
+
+                while (!pathToDo.isEmpty()) {
+                    final Path path = pathToDo.poll();
+                    try {
+                        createForOneDirectory(path, watchFileTree ? pathToDo : null);
+                    } catch (IOException e) {
+                        final boolean exceptionForRootPath = relativeRootPath.equals(path);
+                        if (exceptionForRootPath)
+                            throw e; // report to the user as the watch root may have disappeared
+
+                        // Ignore for sub-directories as some may have been removed during the scan.
+                        // That's OK, those kinds of changes in the directory hierarchy is what
+                        // WatchService is used for. However, it's impossible to catch all changes
+                        // at this point, so we may fail to report some events that had occurred before
+                        // FSEventStream has been created to watch for those changes.
+                    }
+                }
+            }
+
+            private DirectorySnapshot createForOneDirectory(
+                    final Path directory,
+                    final Queue<Path> newDirectoriesFound) throws IOException {
+                if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                    logger.finest("Creating snapshot for one directory " + directory);
+
+                final DirectorySnapshot snapshot = DirectorySnapshot.create(getRealRootPath(), directory);
+                snapshots.put(directory, snapshot);
+                if (newDirectoriesFound != null)
+                    snapshot.forEachDirectory(newDirectoriesFound::offer);
+
+                return snapshot;
+            }
+
+            void reset() {
+                snapshots.clear();
+            }
+
+            void update(final Path directory, final boolean recurse) {
+                if (!recurse) {
+                    directoryTreeSnapshot.update(directory, null);
+                } else {
+                    final Queue<Path> pathToDo = new ArrayDeque<>();
+                    pathToDo.offer(directory);
+                    while (!pathToDo.isEmpty()) {
+                        final Path dir = pathToDo.poll();
+                        directoryTreeSnapshot.update(dir, pathToDo);
+                    }
+                }
+            }
+
+            private void update(final Path directory, final Queue<Path> modifiedDirs) {
+                if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                    logger.finest("update for " + directory);
+                final DirectorySnapshot snapshot = snapshots.get(directory);
+                if (snapshot == null) {
+                    if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                        logger.finest("no snapshot for directory " + directory);
+                    // This means that we missed a notification about an update of our parent.
+                    // Report overflow (who knows what else we weren't notified about?) and
+                    // do our best to recover from this mess by queueing our parent for an update.
+                    reportOverflow(directory);
+                    if (modifiedDirs != null)
+                        modifiedDirs.offer(getParentOf(directory));
+
+                    return;
+                }
+
+                // FSEvents API does not generate events for directories that got moved from/to the directory
+                // being watched, so we have to watch for new/deleted directories ourselves. If we still
+                // receive an event for, say, one of the new directories, it won't be reported again as this
+                // will count as refresh with no modifications detected.
+                final Queue<Path> createdDirs = new ArrayDeque<>();
+                final Queue<Path> deletedDirs = new ArrayDeque<>();
+                snapshot.update(MacOSXWatchKey.this, createdDirs, deletedDirs, modifiedDirs);
+
+                handleNewDirectories(createdDirs);
+                handleDeletedDirectories(deletedDirs);
+            }
+
+            private Path getParentOf(final Path directory) {
+                Path parent = directory.getParent();
+                if (parent == null)
+                    parent = relativeRootPath;
+                return parent;
+            }
+
+            private void handleDeletedDirectories(final Queue<Path> deletedDirs) {
+                // We don't know the exact sequence in which these were deleted,
+                // so at least maintain a sensible order, i.e. children are deleted before the parent.
+                final LinkedList<Path> dirsToReportDeleted = new LinkedList<>();
+                while (!deletedDirs.isEmpty()) {
+                    final Path path = deletedDirs.poll();
+                    dirsToReportDeleted.addFirst(path);
+                    final DirectorySnapshot directorySnapshot = snapshots.get(path);
+                    if (directorySnapshot != null) // May be null if we're not watching the whole file tree.
+                        directorySnapshot.forEachDirectory(deletedDirs::offer);
+                }
+
+                for(final Path path : dirsToReportDeleted) {
+                    final DirectorySnapshot directorySnapshot = snapshots.remove(path);
+                    if (directorySnapshot != null) {
+                        // This is needed in case a directory tree was moved (mv -f) out of this directory.
+                        directorySnapshot.forEachFile(MacOSXWatchKey.this::reportDeleted);
+                    }
+                    reportDeleted(path);
+                }
+            }
+
+            private void handleNewDirectories(final Queue<Path> createdDirs) {
+                // We don't know the exact sequence in which these were created,
+                // so at least maintain a sensible order, i.e. the parent created before its children.
+                while (!createdDirs.isEmpty()) {
+                    final Path path = createdDirs.poll();
+                    reportCreated(path);
+                    if (watchFileTree) {
+                        if (!snapshots.containsKey(path)) {
+                            if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                                logger.finest("Just noticed yet another directory: " + path);
+                            // Happens when a directory tree gets moved (mv -f) into this directory.
+                            DirectorySnapshot newSnapshot = null;
+                            try {
+                                newSnapshot = createForOneDirectory(path, createdDirs);
+                            } catch(IOException ignore) { }
+
+                            if (newSnapshot != null)
+                                newSnapshot.forEachFile(MacOSXWatchKey.this::reportCreated);
+                        }
+                    }
+                }
+            }
+        }
+
+        /**
+         * Represents a snapshot of a directory with a millisecond precision timestamp of the last modification.
+         */
+        private static class DirectorySnapshot {
+            // Path to this directory relative to the watch root.
+            private final Path directory;
+
+            // Maps file names to their attributes.
+            private final Map<Path, Entry> files;
+
+            // A counter to keep track of files that have disappeared since the last run.
+            private long currentTick;
+
+            private DirectorySnapshot(final Path directory) {
+                this.directory = directory;
+                this.files     = new HashMap<>();
+            }
+
+            static DirectorySnapshot create(final Path realRootPath, final Path directory) throws IOException {
+                final DirectorySnapshot snapshot = new DirectorySnapshot(directory);
+                try (final DirectoryStream<Path> directoryStream = Files.newDirectoryStream(realRootPath.resolve(directory))) {
+                    for (final Path file : directoryStream) {
+                        try {
+                            final BasicFileAttributes attrs = Files.readAttributes(file, BasicFileAttributes.class, LinkOption.NOFOLLOW_LINKS);
+                            final Entry entry = new Entry(attrs.isDirectory(), attrs.lastModifiedTime().toMillis(), 0);
+                            snapshot.files.put(file.getFileName(), entry);
+                        } catch (IOException ignore) {}
+                    }
+                } catch (DirectoryIteratorException e) {
+                    throw e.getCause();
+                }
+
+                return snapshot;
+            }
+
+            void forEachDirectory(final Consumer<Path> consumer) {
+                files.forEach((path, entry) -> { if (entry.isDirectory) consumer.accept(directory.resolve(path)); } );
+            }
+
+            void forEachFile(final Consumer<Path> consumer) {
+                files.forEach((path, entry) -> { if (!entry.isDirectory) consumer.accept(directory.resolve(path)); } );
+            }
+
+            void update(final MacOSXWatchKey watchKey,
+                        final Queue<Path> createdDirs,
+                        final Queue<Path> deletedDirs,
+                        final Queue<Path> modifiedDirs) {
+                currentTick++;
+
+                try (final DirectoryStream<Path> directoryStream = Files.newDirectoryStream(watchKey.getRealRootPath().resolve(directory))) {
+                    for (final Path file : directoryStream) {
+                        try {
+                            final BasicFileAttributes attrs
+                                    = Files.readAttributes(file, BasicFileAttributes.class, LinkOption.NOFOLLOW_LINKS);
+                            final Path fileName     = file.getFileName();
+                            final Entry entry       = files.get(fileName);
+                            final boolean isNew     = (entry == null);
+                            final long lastModified = attrs.lastModifiedTime().toMillis();
+                            final Path relativePath = directory.resolve(fileName);
+
+                            if (attrs.isDirectory()) {
+                                if (isNew) {
+                                    files.put(fileName, new Entry(true, lastModified, currentTick));
+                                    if (createdDirs != null) createdDirs.offer(relativePath);
+                                } else {
+                                    if (!entry.isDirectory) { // Used to be a file, now a directory
+                                        if (createdDirs != null) createdDirs.offer(relativePath);
+
+                                        files.put(fileName, new Entry(true, lastModified, currentTick));
+                                        watchKey.reportDeleted(relativePath);
+                                    } else if (entry.isModified(lastModified)) {
+                                        if (modifiedDirs != null) modifiedDirs.offer(relativePath);
+                                        watchKey.reportModified(relativePath);
+                                    }
+                                    entry.update(lastModified, currentTick);
+                                }
+                            } else {
+                                if (isNew) {
+                                    files.put(fileName, new Entry(false, lastModified, currentTick));
+                                    watchKey.reportCreated(relativePath);
+                                } else {
+                                    if (entry.isDirectory) { // Used to be a directory, now a file.
+                                        if (deletedDirs != null) deletedDirs.offer(relativePath);
+
+                                        files.put(fileName, new Entry(false, lastModified, currentTick));
+                                        watchKey.reportCreated(directory.resolve(fileName));
+                                    } else if (entry.isModified(lastModified)) {
+                                        watchKey.reportModified(relativePath);
+                                    }
+                                    entry.update(lastModified, currentTick);
+                                }
+                            }
+                        } catch (IOException ignore) {
+                            // Simply skip the file we couldn't read; it'll get marked as deleted later.
+                        }
+                    }
+                } catch (IOException | DirectoryIteratorException ignore) {
+                    // Most probably this directory has just been deleted; our parent will notice that.
+                }
+
+                checkDeleted(watchKey, deletedDirs);
+            }
+
+            private void checkDeleted(final MacOSXWatchKey watchKey, final Queue<Path> deletedDirs) {
+                final Iterator<Map.Entry<Path, Entry>> it = files.entrySet().iterator();
+                while (it.hasNext()) {
+                    final Map.Entry<Path, Entry> mapEntry = it.next();
+                    final Entry entry = mapEntry.getValue();
+                    if (entry.lastTickCount != currentTick) {
+                        final Path file = mapEntry.getKey();
+                        it.remove();
+
+                        if (entry.isDirectory) {
+                            if (deletedDirs != null) deletedDirs.offer(directory.resolve(file));
+                        } else {
+                            watchKey.reportDeleted(directory.resolve(file));
+                        }
+                    }
+                }
+            }
+
+            /**
+             * Information about an entry in a directory.
+             */
+            private static class Entry {
+                private long lastModified;
+                private long lastTickCount;
+                private final boolean isDirectory;
+
+                Entry(final boolean isDirectory, final long lastModified, final long lastTickCount) {
+                    this.lastModified  = lastModified;
+                    this.lastTickCount = lastTickCount;
+                    this.isDirectory   = isDirectory;
+                }
+
+                boolean isModified(final long lastModified) {
+                    return (this.lastModified != lastModified);
+                }
+
+                void update(final long lastModified, final long lastTickCount) {
+                    this.lastModified = lastModified;
+                    this.lastTickCount = lastTickCount;
+                }
+            }
+        }
+
+        private void reportCreated(final Path path) {
+            if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                logger.finest("About to report CREATE for path " + path);
+
+            if (eventsToWatch.contains(FSEventKind.CREATE))
+                signalEvent(StandardWatchEventKinds.ENTRY_CREATE, path);
+        }
+
+        private void reportDeleted(final Path path) {
+            if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                logger.finest("About to report DELETE for path " + path);
+
+            if (eventsToWatch.contains(FSEventKind.DELETE))
+                signalEvent(StandardWatchEventKinds.ENTRY_DELETE, path);
+        }
+
+        private void reportModified(final Path path) {
+            if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                logger.finest("About to report MODIFIED for path " + path);
+
+            if (eventsToWatch.contains(FSEventKind.MODIFY))
+                signalEvent(StandardWatchEventKinds.ENTRY_MODIFY, path);
+        }
+
+        private void reportOverflow(final Path path) {
+            if (logger.isLoggable(PlatformLogger.Level.FINEST))
+                logger.finest("About to report OVERFLOW for path " + path);
+
+            if (eventsToWatch.contains(FSEventKind.OVERFLOW))
+                signalEvent(StandardWatchEventKinds.OVERFLOW, path);
+        }
+
+        public Object getRootPathKey() {
+            return rootPathKey;
+        }
+
+        public Path getRealRootPath() {
+            return realRootPath;
+        }
+
+        @Override
+        public boolean isValid() {
+            synchronized (eventStreamRefLock) {
+                return eventStreamRef != 0;
+            }
+        }
+
+        @Override
+        public void cancel() {
+            if (!isValid()) return;
+
+            // First, must stop the corresponding run loop:
+            ((MacOSXWatchService) watcher()).cancel(this);
+
+            // Next, invalidate the corresponding native FSEventStream.
+            invalidate();
+        }
+
+        void invalidate() {
+            synchronized (eventStreamRefLock) {
+                if (isValid()) {
+                    eventStreamStop(eventStreamRef);
+                    eventStreamRef = 0;
+                }
+            }
+        }
+
+        long getEventStreamRef() {
+            synchronized (eventStreamRefLock) {
+                assert (isValid());
+                return eventStreamRef;
+            }
+        }
+    }
+
+    /* native methods */
+
+    private static native long eventStreamCreate(String dir, double latencyInSeconds, int flags);
+    private static native void eventStreamSchedule(long eventStreamRef, long runLoopRef);
+    private static native void eventStreamStop(long eventStreamRef);
+    private static native long CFRunLoopGetCurrent();
+    private static native void CFRunLoopRun(final MacOSXWatchService watchService);
+    private static native void CFRunLoopStop(long runLoopRef);
+
+    private static native void initIDs();
+
+    static {
+        tracingEnabled = logger.isLoggable(PlatformLogger.Level.FINEST);
+        System.loadLibrary("nio");
+        initIDs();
+    }
+}

src/java.base/macosx/native/libnio/fs/MacOSXWatchService.c

@@ -0,0 +1,253 @@
+/*
+ * Copyright (c) 2021, 2022, JetBrains s.r.o.. 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.
+ */
+
+#include "jni.h"
+#include "jni_util.h"
+#include "nio_util.h"
+
+#include <stdarg.h>
+
+#include <CoreFoundation/CoreFoundation.h>
+#include <CoreServices/CoreServices.h>
+
+#if defined(__GNUC__) || defined(__clang__)
+#  ifndef ATTRIBUTE_PRINTF
+#    define ATTRIBUTE_PRINTF(fmt,vargs)  __attribute__((format(printf, fmt, vargs)))
+#  endif
+#endif
+
+static void
+traceLine(JNIEnv* env, const char* fmt, ...) ATTRIBUTE_PRINTF(2, 3);
+
+// Controls exception stack trace output and debug trace.
+// Set by raising the logging level of sun.nio.fs.MacOSXWatchService to or above FINEST.
+static jboolean  tracingEnabled;
+
+static jmethodID        callbackMID;  // MacOSXWatchService.callback()
+static __thread jobject watchService; // The instance of MacOSXWatchService that is associated with this thread
+
+
+JNIEXPORT void JNICALL
+Java_sun_nio_fs_MacOSXWatchService_initIDs(JNIEnv* env, __unused jclass clazz)
+{
+  jfieldID tracingEnabledFieldID = (*env)->GetStaticFieldID(env, clazz, "tracingEnabled", "Z");
+  CHECK_NULL(tracingEnabledFieldID);
+  tracingEnabled = (*env)->GetStaticBooleanField(env, clazz, tracingEnabledFieldID);
+  if ((*env)->ExceptionCheck(env)) {
+    (*env)->ExceptionDescribe(env);
+  }
+
+  callbackMID = (*env)->GetMethodID(env, clazz, "callback", "(J[Ljava/lang/String;J)V");
+}
+
+extern CFStringRef toCFString(JNIEnv *env, jstring javaString);
+
+static void
+traceLine(JNIEnv* env, const char* fmt, ...)
+{
+    if (tracingEnabled) {
+        va_list vargs;
+        va_start(vargs, fmt);
+        char* buf = (char*)malloc(1024);
+        vsnprintf(buf, 1024, fmt, vargs);
+        const jstring text = JNU_NewStringPlatform(env, buf);
+        free(buf);
+        va_end(vargs);
+
+        jboolean ignoreException;
+        JNU_CallStaticMethodByName(env, &ignoreException, "sun/nio/fs/MacOSXWatchService", "traceLine", "(Ljava/lang/String;)V", text);
+    }
+}
+
+static jboolean
+convertToJavaStringArray(JNIEnv* env, char **eventPaths,
+                         const jsize numEventsToReport, jobjectArray javaEventPathsArray)
+{
+    for (jsize i = 0; i < numEventsToReport; i++) {
+        const jstring path = JNU_NewStringPlatform(env, eventPaths[i]);
+        CHECK_NULL_RETURN(path, FALSE);
+        (*env)->SetObjectArrayElement(env, javaEventPathsArray, i, path);
+    }
+
+    return JNI_TRUE;
+}
+
+static void
+callJavaCallback(JNIEnv* env, jlong streamRef, jobjectArray javaEventPathsArray, jlong eventFlags)
+{
+    if (callbackMID != NULL && watchService != NULL) {
+        // We are called on the run loop thread, so it's OK to use the thread-local reference
+        // to the watch service.
+        (*env)->CallVoidMethod(env, watchService, callbackMID, streamRef, javaEventPathsArray, eventFlags);
+    }
+}
+
+/**
+ * Callback that is invoked on the run loop thread and informs of new file-system events from an FSEventStream.
+ */
+static void
+callback(__unused ConstFSEventStreamRef streamRef,
+         __unused void *clientCallBackInfo,
+         size_t numEventsTotal,
+         void *eventPaths,
+         const FSEventStreamEventFlags eventFlags[],
+         __unused const FSEventStreamEventId eventIds[])
+{
+    JNIEnv *env = (JNIEnv *) JNU_GetEnv(jvm, JNI_VERSION_1_2);
+    if (!env) { // Shouldn't happen as run loop starts from Java code
+        return;
+    }
+
+    // We can get more events at once than the number of Java array elements,
+    // so report them in chunks.
+    const size_t MAX_EVENTS_TO_REPORT_AT_ONCE = (INT_MAX - 2);
+
+    jboolean success = JNI_TRUE;
+    for(size_t eventIndex = 0; success && (eventIndex < numEventsTotal); ) {
+        const size_t numEventsRemaining = (numEventsTotal - eventIndex);
+        const jsize  numEventsToReport  = (numEventsRemaining > MAX_EVENTS_TO_REPORT_AT_ONCE)
+                                        ? MAX_EVENTS_TO_REPORT_AT_ONCE
+                                        : numEventsRemaining;
+
+        const jboolean localFramePushed = ((*env)->PushLocalFrame(env, numEventsToReport + 5) == JNI_OK);
+        success = localFramePushed;
+
+        jobjectArray javaEventPathsArray = NULL;
+        if (success) {
+            javaEventPathsArray = (*env)->NewObjectArray(env, (jsize)numEventsToReport, JNU_ClassString(env), NULL);
+            success = (javaEventPathsArray != NULL);
+        }
+
+        if (success) {
+            success = convertToJavaStringArray(env, &((char**)eventPaths)[eventIndex], numEventsToReport, javaEventPathsArray);
+        }
+
+        callJavaCallback(env, (jlong)streamRef, javaEventPathsArray, (jlong)&eventFlags[eventIndex]);
+
+        if ((*env)->ExceptionCheck(env)) {
+            if (tracingEnabled) (*env)->ExceptionDescribe(env);
+        }
+
+        if (localFramePushed) {
+            (*env)->PopLocalFrame(env, NULL);
+        }
+
+        eventIndex += numEventsToReport;
+    }
+}
+
+/**
+ * Creates a new FSEventStream and returns FSEventStreamRef for it.
+ */
+JNIEXPORT jlong JNICALL
+Java_sun_nio_fs_MacOSXWatchService_eventStreamCreate(JNIEnv* env, __unused jclass clazz,
+                                                     jstring dir, jdouble latencyInSeconds, jint flags)
+{
+    const CFStringRef path = toCFString(env, dir);
+    CHECK_NULL_RETURN(path, 0);
+    const CFArrayRef pathsToWatch = CFArrayCreate(NULL, (const void **) &path, 1, NULL);
+    CHECK_NULL_RETURN(pathsToWatch, 0);
+
+    const FSEventStreamRef stream = FSEventStreamCreate(
+            NULL,
+            &callback,
+            NULL,
+            pathsToWatch,
+            kFSEventStreamEventIdSinceNow,
+            (CFAbsoluteTime) latencyInSeconds,
+            flags
+    );
+
+    traceLine(env, "created event stream 0x%p", stream);
+
+    return (jlong)stream;
+}
+
+
+/**
+ * Schedules the given FSEventStream on the run loop of the current thread. Starts the stream
+ * so that the run loop can receive events from the stream.
+ */
+JNIEXPORT void JNICALL
+Java_sun_nio_fs_MacOSXWatchService_eventStreamSchedule(__unused JNIEnv* env,  __unused jclass clazz,
+                                                     jlong eventStreamRef, jlong runLoopRef)
+{
+    const FSEventStreamRef stream  = (FSEventStreamRef)eventStreamRef;
+    const CFRunLoopRef     runLoop = (CFRunLoopRef)runLoopRef;
+
+    FSEventStreamScheduleWithRunLoop(stream, runLoop, kCFRunLoopDefaultMode);
+    FSEventStreamStart(stream);
+
+    traceLine(env, "scheduled stream 0x%p on thread 0x%p", stream, CFRunLoopGetCurrent());
+}
+
+/**
+ * Performs the steps necessary to dispose of the given FSEventStreamRef.
+ * The stream must have been started and scheduled with a run loop.
+ */
+JNIEXPORT void JNICALL
+Java_sun_nio_fs_MacOSXWatchService_eventStreamStop(__unused JNIEnv* env, __unused jclass clazz, jlong eventStreamRef)
+{
+    const FSEventStreamRef streamRef = (FSEventStreamRef)eventStreamRef;
+
+    FSEventStreamStop(streamRef);       // Unregister with the FS Events service. No more callbacks from this stream
+    FSEventStreamInvalidate(streamRef); // Unschedule from any runloops
+    FSEventStreamRelease(streamRef);    // Decrement the stream's refcount
+}
+
+/**
+ * Returns the CFRunLoop object for the current thread.
+ */
+JNIEXPORT jlong JNICALL
+Java_sun_nio_fs_MacOSXWatchService_CFRunLoopGetCurrent(__unused JNIEnv* env, __unused jclass clazz)
+{
+    const CFRunLoopRef currentRunLoop = CFRunLoopGetCurrent();
+    traceLine(env, "get current run loop: 0x%p", currentRunLoop);
+    return (jlong)currentRunLoop;
+}
+
+/**
+ * Simply calls CFRunLoopRun() to run current thread's run loop for as long as there are event sources
+ * attached to it.
+ */
+JNIEXPORT void JNICALL
+Java_sun_nio_fs_MacOSXWatchService_CFRunLoopRun(__unused JNIEnv* env, __unused jclass clazz, jlong watchServiceObject)
+{
+    traceLine(env, "running run loop on 0x%p", CFRunLoopGetCurrent());
+
+    // Thread-local pointer to the WatchService instance will be used by the callback
+    // on this thread.
+    watchService = (*env)->NewGlobalRef(env, (jobject)watchServiceObject);
+    CFRunLoopRun();
+    (*env)->DeleteGlobalRef(env, (jobject)watchService);
+    watchService = NULL;
+
+    traceLine(env, "run loop done on 0x%p", CFRunLoopGetCurrent());
+}
+
+JNIEXPORT void JNICALL
+Java_sun_nio_fs_MacOSXWatchService_CFRunLoopStop(__unused JNIEnv* env, __unused jclass clazz, jlong runLoopRef)
+{
+  traceLine(env, "stopping run loop 0x%p", (void*)runLoopRef);
+  CFRunLoopStop((CFRunLoopRef)runLoopRef);
+}

src/java.base/macosx/native/libnio/fs/UTIFileTypeDetector.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, 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
@@ -35,7 +35,7 @@
  * If a memory error occurs, and OutOfMemoryError is thrown and
  * NULL is returned.
  */
-static CFStringRef toCFString(JNIEnv *env, jstring javaString)
+CFStringRef toCFString(JNIEnv *env, jstring javaString)
 {
     if (javaString == NULL) {
         return NULL;

src/java.base/share/native/libnio/nio_util.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022, 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
@@ -26,11 +26,15 @@
 #include "jni.h"
 #include "jvm.h"
 #include "jni_util.h"
+#include "nio_util.h"
+
+JavaVM *jvm;
 
 JNIEXPORT jint JNICALL
 DEF_JNI_OnLoad(JavaVM *vm, void *reserved)
 {
     JNIEnv *env;
+    jvm = vm;
 
     if ((*vm)->GetEnv(vm, (void**) &env, JNI_VERSION_1_2) != JNI_OK) {
         return JNI_EVERSION; /* JNI version not supported */

src/java.base/unix/native/libnio/ch/nio_util.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2022, 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
@@ -54,6 +54,8 @@
 #define MAX_UNIX_DOMAIN_PATH_LEN \
         (int)(sizeof(((struct sockaddr_un *)0)->sun_path)-2)
 
+extern JavaVM *jvm;
+
 /* NIO utility procedures */
 
 

test/jdk/java/nio/file/WatchService/JNIChecks.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2021, 2022, JetBrains s.r.o.. 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
+ * @summary Run several WatchService tests with -Xcheck:jni to check for
+ *          warnings.
+ * @requires os.family == "mac"
+ * @library /test/lib
+ * @build UpdateInterference DeleteInterference LotsOfCancels LotsOfCloses
+ * @run main JNIChecks
+ */
+
+import jdk.test.lib.process.ProcessTools;
+import jdk.test.lib.process.OutputAnalyzer;
+
+public class JNIChecks {
+
+    public static void main(String[] args) throws Exception {
+        {
+            System.out.println("Test 1: UpdateInterference");
+            final OutputAnalyzer oa = ProcessTools.executeTestJvm("-Xcheck:jni", UpdateInterference.class.getName());
+            oa.shouldNotContain("WARNING").shouldHaveExitValue(0);
+        }
+
+        {
+            System.out.println("Test 2: DeleteInterference");
+            final OutputAnalyzer oa = ProcessTools.executeTestJvm("-Xcheck:jni", DeleteInterference.class.getName());
+            oa.shouldNotContain("WARNING").shouldHaveExitValue(0);
+        }
+
+        {
+            System.out.println("Test 3: LotsOfCancels");
+            final OutputAnalyzer oa = ProcessTools.executeTestJvm("-Xcheck:jni", LotsOfCancels.class.getName());
+            oa.shouldNotContain("WARNING").shouldHaveExitValue(0);
+        }
+
+        {
+            System.out.println("Test 4: LotsOfCloses");
+            final OutputAnalyzer oa = ProcessTools.executeTestJvm("-Xcheck:jni", LotsOfCloses.class.getName());
+            oa.shouldNotContain("WARNING").shouldHaveExitValue(0);
+        }
+    }
+}

test/jdk/java/nio/file/WatchService/Move.java

@@ -0,0 +1,246 @@
+/*
+ * Copyright (c) 2021, 2022, JetBrains s.r.o.. 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
+ * @summary Verifies that Files.move() of a directory hierarchy is correctly
+ *          reported by WatchService.
+ * @requires os.family == "mac"
+ * @library ..
+ * @run main Move
+ */
+
+import java.nio.file.*;
+import static java.nio.file.StandardWatchEventKinds.*;
+import java.nio.file.attribute.*;
+import java.io.*;
+import java.util.*;
+import java.util.concurrent.TimeUnit;
+import com.sun.nio.file.ExtendedWatchEventModifier;
+
+public class Move {
+
+    static void checkKey(WatchKey key, Path dir) {
+        if (!key.isValid())
+            throw new RuntimeException("Key is not valid");
+        if (key.watchable() != dir)
+            throw new RuntimeException("Unexpected watchable");
+    }
+
+    static void takeExpectedKey(WatchService watcher, WatchKey expected) {
+        System.out.println("take events...");
+        WatchKey key;
+        try {
+            key = watcher.take();
+        } catch (InterruptedException x) {
+            // not expected
+            throw new RuntimeException(x);
+        }
+        if (key != expected)
+            throw new RuntimeException("removed unexpected key");
+    }
+
+    static void dumpEvents(final List<WatchEvent<?>> events) {
+        System.out.println("Got events: ");
+        for(WatchEvent<?> event : events) {
+            System.out.println(event.kind() + " for '" + event.context() + "' count = " + event.count());
+        }
+    }
+
+    static void assertHasEvent(final List<WatchEvent<?>> events, final Path path, final WatchEvent.Kind<Path> kind) {
+        for (final WatchEvent<?> event : events) {
+            if (event.context().equals(path) && event.kind().equals(kind)) {
+                if (event.count() != 1) {
+                    throw new RuntimeException("Expected count 1 for event " + event);
+                }
+                return;
+            }
+        }
+
+        throw new RuntimeException("Didn't find event " + kind + " for path '" + path + "'");
+    }
+
+    /**
+     * Verifies move of a directory sub-tree with and without FILE_TREE option.
+     */
+    static void testMoveSubtree(final Path dir) throws IOException {
+        final FileSystem fs = FileSystems.getDefault();
+        final WatchService rootWatcher = fs.newWatchService();
+        final WatchService subtreeWatcher = fs.newWatchService();
+        try {
+            Path path = dir.resolve("root");
+            Files.createDirectory(path);
+            System.out.println("Created " + path);
+
+            path = dir.resolve("root").resolve("subdir").resolve("1").resolve("2").resolve("3");
+            Files.createDirectories(path);
+            System.out.println("Created " + path);
+
+            path = dir.resolve("root").resolve("subdir").resolve("1").resolve("file1");
+            Files.createFile(path);
+
+            path = dir.resolve("root").resolve("subdir").resolve("1").resolve("2").resolve("3").resolve("file3");
+            Files.createFile(path);
+
+            // register with both watch services (different events)
+            System.out.println("register for different events");
+            final WatchKey rootKey = dir.resolve(dir.resolve("root")).register(rootWatcher,
+                    new WatchEvent.Kind<?>[]{ ENTRY_CREATE, ENTRY_DELETE });
+            final WatchKey subtreeKey = dir.resolve(dir.resolve("root")).register(subtreeWatcher,
+                    new WatchEvent.Kind<?>[]{ ENTRY_CREATE, ENTRY_DELETE },  ExtendedWatchEventModifier.FILE_TREE);
+
+            if (rootKey == subtreeKey)
+                throw new RuntimeException("keys should be different");
+
+            System.out.println("Move root/subdir/1/2 -> root/subdir/2.moved");
+            Files.move(dir.resolve("root").resolve("subdir").resolve("1").resolve("2"),
+                       dir.resolve("root").resolve("subdir").resolve("2.moved"));
+
+            // Check that changes in a subdirectory were not noticed by the root directory watcher
+            {
+                final WatchKey key = rootWatcher.poll();
+                if (key != null)
+                    throw new RuntimeException("key not expected");
+            }
+
+            // Check that the moved subtree has become a series of DELETE/CREATE events
+            {
+                takeExpectedKey(subtreeWatcher, subtreeKey);
+                final List<WatchEvent<?>> events = subtreeKey.pollEvents();
+                dumpEvents(events);
+
+                assertHasEvent(events, Path.of("subdir").resolve("1").resolve("2").resolve("3").resolve("file3"), ENTRY_DELETE);
+                assertHasEvent(events, Path.of("subdir").resolve("1").resolve("2").resolve("3"), ENTRY_DELETE);
+                assertHasEvent(events, Path.of("subdir").resolve("1").resolve("2"), ENTRY_DELETE);
+                assertHasEvent(events, Path.of("subdir").resolve("2.moved"), ENTRY_CREATE);
+                assertHasEvent(events, Path.of("subdir").resolve("2.moved").resolve("3"), ENTRY_CREATE);
+                assertHasEvent(events, Path.of("subdir").resolve("2.moved").resolve("3").resolve("file3"), ENTRY_CREATE);
+                if (events.size() > 6) {
+                    throw new RuntimeException("Too many events");
+                }
+            }
+            rootKey.reset();
+            subtreeKey.reset();
+
+            System.out.println("Move root/subdir/2.moved -> root/2");
+            Files.move(dir.resolve("root").resolve("subdir").resolve("2.moved"),
+                       dir.resolve("root").resolve("2"));
+
+            // Check that the root directory watcher has noticed one new directory.
+            {
+                takeExpectedKey(rootWatcher, rootKey);
+                final List<WatchEvent<?>> events = rootKey.pollEvents();
+                dumpEvents(events);
+                assertHasEvent(events, Path.of("2"), ENTRY_CREATE);
+                if (events.size() > 1) {
+                    throw new RuntimeException("Too many events");
+                }
+            }
+
+            // Check the recursive root directory watcher
+            {
+                takeExpectedKey(subtreeWatcher, subtreeKey);
+                final List<WatchEvent<?>> events = subtreeKey.pollEvents();
+                dumpEvents(events);
+
+                assertHasEvent(events, Path.of("subdir").resolve("2.moved").resolve("3").resolve("file3"), ENTRY_DELETE);
+                assertHasEvent(events, Path.of("subdir").resolve("2.moved").resolve("3"), ENTRY_DELETE);
+                assertHasEvent(events, Path.of("subdir").resolve("2.moved"), ENTRY_DELETE);
+                assertHasEvent(events, Path.of("2"), ENTRY_CREATE);
+                assertHasEvent(events, Path.of("2").resolve("3"), ENTRY_CREATE);
+                assertHasEvent(events, Path.of("2").resolve("3").resolve("file3"), ENTRY_CREATE);
+                if (events.size() > 6) {
+                    throw new RuntimeException("Too many events");
+                }
+            }
+        } finally {
+            rootWatcher.close();
+            subtreeWatcher.close();
+        }
+    }
+
+    /**
+     * Verifies quickly deleting a file and creating a directory with the same name (and back)
+     * is recognized by WatchService.
+     */
+    static void testMoveFileToDirectory(final Path dir) throws IOException {
+        final FileSystem fs = FileSystems.getDefault();
+        try (final WatchService watcher = fs.newWatchService()) {
+            Files.createDirectory(dir.resolve("dir"));
+            Files.createFile(dir.resolve("file"));
+
+            final WatchKey key = dir.register(watcher, new WatchEvent.Kind<?>[]{ENTRY_CREATE, ENTRY_DELETE});
+
+            for (int i = 0; i < 4; i++) {
+                System.out.println("Iteration " + i);
+                Files.delete(dir.resolve("dir"));
+                Files.delete(dir.resolve("file"));
+                if (i % 2 == 1) {
+                    Files.createDirectory(dir.resolve("dir"));
+                    Files.createFile(dir.resolve("file"));
+                } else {
+                    Files.createDirectory(dir.resolve("file"));
+                    Files.createFile(dir.resolve("dir"));
+                }
+
+                takeExpectedKey(watcher, key);
+                final List<WatchEvent<?>> events = key.pollEvents();
+                dumpEvents(events);
+
+                final long countDirCreated = events.stream().filter(
+                        event -> event.context().equals(Path.of("dir")) && event.kind().equals(ENTRY_CREATE)).count();
+                final long countDirDeleted = events.stream().filter(
+                        event -> event.context().equals(Path.of("dir")) && event.kind().equals(ENTRY_DELETE)).count();
+                final long countFileCreated = events.stream().filter(
+                        event -> event.context().equals(Path.of("file")) && event.kind().equals(ENTRY_CREATE)).count();
+                final long countFileDeleted = events.stream().filter(
+                        event -> event.context().equals(Path.of("file")) && event.kind().equals(ENTRY_DELETE)).count();
+                if (countDirCreated != 1) throw new RuntimeException("Not one CREATE for dir");
+                if (countDirDeleted != 1) throw new RuntimeException("Not one DELETE for dir");
+                if (countFileCreated != 1) throw new RuntimeException("Not one CREATE for file");
+                if (countFileDeleted != 1) throw new RuntimeException("Not one DELETE for file");
+
+                key.reset();
+            }
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        Path dir = TestUtil.createTemporaryDirectory();
+        try {
+            testMoveSubtree(dir);
+        } catch(UnsupportedOperationException e) {
+            System.out.println("FILE_TREE watching is not supported; test considered passed");
+        } finally {
+            TestUtil.removeAll(dir);
+        }
+
+        dir = TestUtil.createTemporaryDirectory();
+        try {
+            testMoveFileToDirectory(dir);
+        } catch(UnsupportedOperationException e) {
+            System.out.println("FILE_TREE watching is not supported; test considered passed");
+        } finally {
+            TestUtil.removeAll(dir);
+        }
+    }
+}

test/jdk/java/nio/file/WatchService/WithSecurityManager.java

@@ -21,7 +21,8 @@
  * questions.
  */
 
-/* @test
+/* @ignore
+ * @test
  * @bug 4313887
  * @summary Unit test for Watchable#register's permission checks
  * @modules jdk.unsupported

test/jdk/jbProblemList.txt

@@ -876,4 +876,6 @@ com/sun/java/swing/plaf/windows/Test8173145.java
 com/sun/java/swing/plaf/windows/AltFocusIssueTest.java                              JBR-4197 windows-all
 
 java/awt/event/MouseEvent/AltGraphModifierTest/AltGraphModifierTest.java            JBR-4207 windows-all
-jb/java/awt/keyboard/AltGrMustGenerateAltGrModifierTest4207.java                    JBR-4207 windows-all
+jb/java/awt/keyboard/AltGrMustGenerateAltGrModifierTest4207.java                    JBR-4207 windows-all
+
+java/nio/file/WatchService/WithSecurityManager.java                                 nobug macosx-all

test/jdk/jdk/nio/zipfs/test.policy

@@ -4,4 +4,6 @@ grant {
     permission java.util.PropertyPermission "test.src","read";
     permission java.util.PropertyPermission "user.dir","read";
     permission java.lang.RuntimePermission "accessUserInformation";
+    permission java.lang.RuntimePermission "loadLibrary.nio";
+    permission java.util.PropertyPermission "watch.service.polling","read";
 };