SequencedCollection<String> sequenced = CollectionsUtil.newLinkedHashSet();
String first = CollectionsUtil.getFirst(sequenced);
String last = CollectionsUtil.getLast(sequenced);
SequencedCollection<String> reversed = CollectionsUtil.reversed(sequenced);

// Specialized collections
LruHashMap<String, Object> lruCache = new LruHashMap<>(100); // LRU cache with max 100 entries
CaseInsensitiveMap<String> configMap = new CaseInsensitiveMap<>();
```

    //                                                                           Attribute
    //

    /**
     * The helper for related content.
     */
    @Resource
    protected RelatedContentHelper relatedContentHelper;

    /**
     * The helper for related queries.
     */
    @Resource
    protected RelatedQueryHelper relatedQueryHelper;

import org.codelibs.core.concurrent.CommonPoolUtil;
import org.codelibs.core.lang.ThreadUtil;

/**
 * The abstract helper for configuration.
 *
 * This class provides a basic framework for managing configurations that can be reloaded.
 * It includes functionality for updating configurations in a separate thread and controlling the reloading interval.
 */
public abstract class AbstractConfigHelper {

    /**
     * Default constructor.
     */

 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.exception;

/**
 * Exception thrown when theme-related operations fail.
 * This exception is used for errors during theme installation, uninstallation, or configuration.
 */
public class ThemeException extends FessSystemException {

import java.util.Random;
import java.util.RandomAccess;
import org.jspecify.annotations.NullUnmarked;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Tests for repeated node and edge addition and removal in a {@link Network}. */
@RunWith(JUnit4.class)

@NullUnmarked
public final class NetworkMutationTest {
  private static final int NUM_TRIALS = 5;

import java.util.Random;
import java.util.RandomAccess;
import org.jspecify.annotations.NullUnmarked;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Tests for repeated node and edge addition and removal in a {@link Graph}. */
@RunWith(JUnit4.class)

@NullUnmarked
public final class GraphMutationTest {
  private static final int NUM_TRIALS = 50;

import kotlin.contracts.InvocationKind
import kotlin.contracts.contract
import okhttp3.internal.assertionsEnabled

/**
 * Marker interface for objects that use the JVM's `synchronized` mechanism and the related
 * `wait()` and `notify()` functions.
 *
 * The Lockable interface is particularly handy because it ensures we lock the right `this` when
 * there are multiple `this` objects in scope.
 */
interface Lockable

![Events Diagram](../assets/images/******@****.***)

### Availability

 * features}, the features supported by the iterator; and {@code expectedElements}, the elements the
 * iterator should return in order.
 *
 * <p>The items in {@code elementsToInsert} will be repeated if {@code steps} is larger than the
 * number of provided elements.
 *
 * @author Chris Povirk
 */
@GwtCompatible
@NullMarked
public abstract class ListIteratorTester<E extends @Nullable Object>

 */
package org.codelibs.fess.util;

import java.util.Arrays;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Utility class for JVM-related operations.
 * This class provides methods for handling JVM options and version detection.
 */
public final class JvmUtil {
    private static final Pattern VERSION_PREFIX_PATTERN = Pattern.compile("([0-9]+)(\\-?):(.*)");