* there would exist a perfect hash function mapping threads to
   * slots that eliminates collisions. When we reach capacity, we
   * search for this mapping by randomly varying the hash codes of
   * colliding threads.  Because search is random, and collisions
   * only become known via CAS failures, convergence can be slow,
   * and because threads are typically not bound to CPUS forever,
   * may not occur at all. However, despite these limitations,

import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * The {@code ThreadSafe} annotation can be used to indicate a given type
 * is thread safe.  {@link Immutable} objects are automatically thread safe.
 *
 * @see Immutable
 * @see NotThreadSafe
 * @since 4.0.0
 */
@Experimental
@Documented
@Retention(RetentionPolicy.CLASS)
@Target(ElementType.TYPE)

    service.setPort(9200);
});
```

## Performance Tuning

### Thread Configuration

```java
// Optimize thread pool settings
crawler.crawlerContext.setNumOfThread(20);           // Number of crawler threads
crawler.crawlerContext.setMaxThreadCheckCount(50);   // Thread monitoring frequency
```

### Connection Pool Tuning

```java

    }

    /**
     * Installs the specified artifact in a background thread.
     * Also removes any previously installed versions of the same plugin.
     *
     * @param artifact the artifact to install
     */
    public static void installArtifact(final Artifact artifact) {
        new Thread(() -> {
            final PluginHelper pluginHelper = ComponentUtil.getPluginHelper();

@J2ktIncompatible
@GwtIncompatible
public interface FinalizableReference {
  /**
   * Invoked on a background thread after the referent has been garbage collected unless security
   * restrictions prevented starting a background thread, in which case this method is invoked when
   * new references are created.
   */
  void finalizeReferent();

 * methods that they depend on are thread-safe.
 *
 * @author Kevin Bourrillion
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible
public abstract class ForwardingSet<E extends @Nullable Object> extends ForwardingCollection<E>
    implements Set<E> {
  // TODO(lowasser): identify places where thread safety is actually lost

 * currently supporting Kryo and JavaBin serialization formats. The serializer
 * type is determined by the crawler data serializer configuration.
 * </p>
 * <p>
 * The class is thread-safe and uses ThreadLocal to maintain Kryo instances
 * per thread to avoid synchronization overhead.
 * </p>
 *
 */
public class DataSerializer {

    /** Logger for this class. */

 */
@GwtCompatible
final class Platform {
  private Platform() {}

  /** Returns a thread-local 1024-char array. */
  static char[] charBufferFromThreadLocal() {
    // requireNonNull accommodates Android's @RecentlyNullable annotation on ThreadLocal.get
    return requireNonNull(DEST_TL.get());
  }

  /**
   * A thread-local destination buffer to keep us from creating new buffers. The starting size is

            mojos.put(Thread.currentThread(), mojoDescriptor);
            boolean aggregator = mojoDescriptor.isAggregator();
            acquiredAggregatorLock = aggregator ? aggregatorLock.writeLock() : aggregatorLock.readLock();
            acquiredProjectLock = getProjectLock(session);
            if (!acquiredAggregatorLock.tryLock()) {
                Thread owner = aggregatorLock.getOwner();

      assertThat(e).hasMessageThat().isEqualTo("Cannot get() on a pending future.");
    }
  }

  static void verifyThreadWasNotInterrupted() {
    // There is no thread interruption in GWT, so there's nothing to do.
  }

  static void clearInterrupt() {
    // There is no thread interruption in GWT, so there's nothing to do.
  }

  static <V extends @Nullable Object> V getDoneFromTimeoutOverload(Future<V> future)