// When - Release session to trigger cleanup
        session.release();

        // Then - Trees should be cleared (we can't directly verify as it's internal,
        // but the cleanup code with synchronized block ensures it happens atomically)
        // The important part is that no exception occurs and the operation is atomic
    }

    /**
     * Test concurrent acquire and release operations.
     */

    The correct order is:
            public
            protected
            private
            abstract
            static
            final
            transient
            volatile
            synchronized
            native
            strictfp
    -->
    <module name="ModifierOrder" />

    <!-- Checks that we don't include modifier where they are implied. For

 * strategies.
 *
 * <ul>
 *   <li>SafeAtomicHelper: uses Atomic FieldsUpdaters to implement synchronization
 *   <li>SynchronizedHelper: uses {@code synchronized} blocks for synchronization
 * </ul>
 *
 * To force selection of our fallback strategies we load {@link AggregateFutureState} (and all of

         *
         * @param newState new lease state
         */
        public synchronized void updateState(int newState) {
            this.leaseState = newState;
            this.lastAccessTime = System.currentTimeMillis();
        }

        /**
         * Increment the epoch value
         */
        public synchronized void incrementEpoch() {
            this.epoch++;
        }

        /**

    protected abstract FileEntry[] getResults();

    /**
     * Closes the enumeration and releases resources.
     *
     * @throws CIFSException if an error occurs during closing
     */
    protected synchronized void doClose() throws CIFSException {
        // otherwise already closed
        if (!this.closed) {
            this.closed = true;
            try {
                doCloseInternal();
            } finally {

- **DI**: LastaFlute container with `@Resource` and XML config

### Core Principles

**Thread Safety**: `AtomicLong` for counters, `volatile` for status flags, synchronized blocks, thread-local storage via `CrawlingParameterUtil`

                synchronized (result) {
                    result.addMissingArtifact(artifact);
                }
            } catch (ArtifactResolutionException e) {
                // This is really a wagon TransferFailedException so something went wrong after we successfully
                // retrieved the metadata.

                synchronized (result) {

        final int[] callCount = { 0 };

        SearchLogHelper mockSearchLogHelper = new SearchLogHelper() {
            @Override
            public void storeSearchLog() {
                synchronized (lock) {
                    callCount[0]++;
                    if (callCount[0] % 2 == 0) {
                        throw new RuntimeException("Even call error");
                    }

                    // be explicitly safe here to avoid interleaving output from multiple test suites
                    synchronized (this) {
                        // make sure we've flushed everything to disk before reading
                        eventWriter.flush();

                        System.err.println("\n\nSuite: " + suite);

     */
    @Override
    public void refresh() throws CIFSException {
        log.debug("Refreshing JAAS credentials");
        this.cachedSubject = null;
    }

    @Override
    public synchronized Subject getSubject() {
        if (this.cachedSubject != null) {
            return this.cachedSubject;
        }

        try {
            log.debug("Logging on");
            LoginContext lc;