public class CollectionRetainAllTester<E> extends AbstractCollectionTester<E> {

  /** A collection of elements to retain, along with a description for use in failure messages. */
  private final class Target {
    private final Collection<E> toRetain;
    private final String description;

    private Target(Collection<E> toRetain, String description) {
      this.toRetain = toRetain;
      this.description = description;
    }

package org.apache.maven.internal.impl;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Provider;
import javax.inject.Singleton;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;

- **Reduced memory allocation** in collection operations and bean copying
- **Improved reflection performance** with cached descriptors and optimized field access
- **Enhanced collection operations** with Java 21 sequenced collections support
- **Better concurrent performance** using modern concurrent collection implementations

## 🔧 Configuration

### Logging Configuration

  @CollectionFeature.Require(absent = KNOWN_ORDER)
  public void testSpliteratorUnknownOrder() {
    SpliteratorTester.of(collection::spliterator).expect(getSampleElements());
  }

  @CollectionFeature.Require(KNOWN_ORDER)
  public void testSpliteratorKnownOrder() {
    SpliteratorTester.of(collection::spliterator).expect(getOrderedElements()).inOrder();
  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)

import static java.util.Collections.singletonList;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Iterators;
import com.google.common.collect.Multimap;
import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.collect.testing.features.MapFeature;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;

   */
  public static boolean elementsEqual(Iterable<?> iterable1, Iterable<?> iterable2) {
    if (iterable1 instanceof Collection && iterable2 instanceof Collection) {
      Collection<?> collection1 = (Collection<?>) iterable1;
      Collection<?> collection2 = (Collection<?>) iterable2;
      if (collection1.size() != collection2.size()) {
        return false;
      }
    }

    StringBuilder sb = newStringBuilderForCollection(collection.size()).append('[');
    boolean first = true;
    for (Object o : collection) {
      if (!first) {
        sb.append(", ");
      }
      first = false;
      if (o == collection) {
        sb.append("(this Collection)");
      } else {
        sb.append(o);
      }
    }
    return sb.append(']').toString();
  }

        """

        and:
        releaseNotes << """
Nothing to write about
        """

        when:

    public Builder<E> addAll(Iterable<? extends E> elements) {
      if (elements instanceof Collection) {
        Collection<?> collection = (Collection<?>) elements;
        ensureRoomFor(collection.size());
        if (collection instanceof ImmutableCollection) {
          ImmutableCollection<?> immutableCollection = (ImmutableCollection<?>) collection;
          size = immutableCollection.copyIntoArray(contents, size);
          return this;

    }
    return derivedSuites;
  }

  private static final class ReserializedSetGenerator<E> implements TestSetGenerator<E> {
    final OneSizeTestContainerGenerator<Collection<E>, E> gen;

    private ReserializedSetGenerator(OneSizeTestContainerGenerator<Collection<E>, E> gen) {
      this.gen = gen;
    }

    @Override
    public SampleElements<E> samples() {
      return gen.samples();
    }

    @Override