return new IllegalArgumentException(
        "Multiple entries with same " + conflictDescription + ": " + entry1 + " and " + entry2);
  }

  /**
   * A builder for creating immutable map instances, especially {@code public static final} maps
   * ("constant maps"). Example:
   *
   * {@snippet :
   * static final ImmutableMap<String, Integer> WORD_TO_INT =
   *     new ImmutableMap.Builder<String, Integer>()

 * group, and symbolic links.
 *
 * <p>
 * The class uses Apache Commons Net library for FTP communication. It maintains a queue of FTPClient
 * instances to improve performance by reusing connections.
 * </p>
 *
 * <p>
 * The client can be configured with FTP-specific settings via init parameters, such as:
 * </p>
 * <ul>

import com.google.errorprone.annotations.InlineMeValidationDisabled;
import java.util.logging.Logger;
import org.jspecify.annotations.Nullable;

/**
 * Static utility methods pertaining to {@code String} or {@code CharSequence} instances.
 *
 * @author Kevin Bourrillion
 * @since 3.0
 */
@GwtCompatible
public final class Strings {
  private Strings() {}

  /**
   * Returns the given string if it is non-null; the empty string otherwise.

        assertEquals("Multiple deserializations should produce identical results", deserialized1, deserialized2);
    }

    /**
     * Test that ThreadLocal Kryo instances work correctly
     * This verifies that the ThreadLocal implementation doesn't cause issues
     */
    @Test
    public void test_threadLocalKryo() {

  }

  /*
   * Whenever an implementation uses `instanceof` on a parameter instance, the test has to know that
   * (so much for "black box") and try instances that both do and don't pass the check. The "don't"
   * half of that is more awkward to arrange...
   */
  private static <T> Iterable<T> iterable(Collection<T> collection) {
    // return collection::iterator;

  }

  /*
   * Whenever an implementation uses `instanceof` on a parameter instance, the test has to know that
   * (so much for "black box") and try instances that both do and don't pass the check. The "don't"
   * half of that is more awkward to arrange...
   */
  private static <T> Iterable<T> iterable(Collection<T> collection) {
    // return collection::iterator;

    factory.addExtractor("application/custom", container.getComponent("customExtractor"));
});
```

## Advanced Configuration

### Multi-Instance Crawling

```java
// Create multiple crawler instances
Crawler crawler1 = container.getComponent("crawler");
crawler1.setSessionId("session1");
crawler1.addUrl("https://site1.com");

Crawler crawler2 = container.getComponent("crawler");  

import com.google.common.base.MoreObjects;
import java.util.Objects;
import java.util.concurrent.Callable;
import org.jspecify.annotations.Nullable;

/**
 * Statistics about the performance of a {@link Cache}. Instances of this class are immutable.
 *
 * <p>Cache statistics are incremented according to the following rules:
 *
 * <ul>
 *   <li>When a cache lookup encounters an existing cache entry {@code hitCount} is incremented.

    }
    return false;
  }

  @Override
  public String toString() {
    return asMapOfRanges().toString();
  }

  /**
   * This class is used to serialize ImmutableRangeMap instances. Serializes the {@link
   * #asMapOfRanges()} form.
   */
  private static final class SerializedForm<K extends Comparable<?>, V> implements Serializable {

    private final ImmutableMap<Range<K>, V> mapOfRanges;

import com.google.common.base.MoreObjects;
import java.util.Objects;
import java.util.concurrent.Callable;
import org.jspecify.annotations.Nullable;

/**
 * Statistics about the performance of a {@link Cache}. Instances of this class are immutable.
 *
 * <p>Cache statistics are incremented according to the following rules:
 *
 * <ul>
 *   <li>When a cache lookup encounters an existing cache entry {@code hitCount} is incremented.