Enable debug logging for detailed troubleshooting:

```java
// Add to your logging configuration
logger.debug.org.codelibs.fess.suggest=DEBUG
```

## Contributing

1. Fork the repository
2. Create a feature branch: `git checkout -b feature/amazing-feature`
3. Follow coding standards: `mvn formatter:format`
4. Add tests for new functionality
5. Ensure all tests pass: `mvn test`

  Set<Integer> wrappedSet;
  Set<Integer> copyOfWrappedSet;
  InvalidatableSet<Integer> setToTest;

  @Before
  public void createSets() {
    wrappedSet = new HashSet<>();
    wrappedSet.add(1);
    wrappedSet.add(2);
    wrappedSet.add(3);

    copyOfWrappedSet = ImmutableSet.copyOf(wrappedSet);
    setToTest =
        InvalidatableSet.of(wrappedSet, () -> wrappedSet.contains(1), () -> 1 + "is not present");
  }

  @Test

      BigInteger plusHalfSquared = result.pow(2).add(result).shiftLeft(2).add(ONE);
      BigInteger x4 = x.shiftLeft(2);
      // sqrt(x) < result + 0.5, so 4 * x < (result + 0.5)^2 * 4
      // (result + 0.5)^2 * 4 = (result^2 + result)*4 + 1
      assertTrue(x4.compareTo(plusHalfSquared) < 0);
      BigInteger minusHalfSquared = result.pow(2).subtract(result).shiftLeft(2).add(ONE);

      List<E> targetElements = new ArrayList<>();
      Iterator<E> iterator = newTargetIterator();
      for (int j = 0; j < i; j++) {
        targetElements.add(iterator.next());
      }
      iterator.forEachRemaining(targetElements::add);
      if (knownOrder == KnownOrder.KNOWN_ORDER) {
        assertEquals(expectedElements, targetElements);
      } else {

      val result = ArrayList<Header>(headers.size + 4)
      result.add(Header(TARGET_METHOD, request.method))
      result.add(Header(TARGET_PATH, RequestLine.requestPath(request.url)))
      val host = request.header("Host")
      if (host != null) {
        result.add(Header(TARGET_AUTHORITY, host)) // Optional.
      }
      result.add(Header(TARGET_SCHEME, request.url.scheme))

      for (i in 0 until headers.size) {

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  @MapFeature.Require(ALLOWS_NULL_KEYS)
  public void testEquals_containingNullKey() {
    Collection<Entry<K, V>> entries = getSampleEntries(getNumEntries() - 1);
    entries.add(entry(null, v3()));

    resetContainer(getSubjectGenerator().create(entries.toArray()));
    assertTrue(
        "A Map should equal any other Map containing the same entries,"
            + " even if some keys are null.",

    public void neitherOverriddenNorAnnotated(Object o) {
      neitherOverriddenNorAnnotatedEvents.add(o);
    }

    public void overriddenInSubclassNowhereAnnotated(Object o) {
      overriddenInSubclassNowhereAnnotatedEvents.add(o);
    }

    public void overriddenAndAnnotatedInSubclass(Object o) {
      overriddenAndAnnotatedInSubclassEvents.add(o);
    }
  }

  static class SubClass extends SuperClass {
    @Override

 *   ...
 * }
 * </pre>
 *
 * <p>No cascading checks are performed against the return values of methods unless the method is a
 * static factory method. Neither are semantics of mutation methods such as {@code
 * someList.add(obj)} checked. For more detailed discussion of supported and unsupported cases, see
 * {@link #testEquals}, {@link #testNulls} and {@link #testSerializable}.
 *

					ModTime:   baseTime.Add(60 * time.Minute).UnixNano(),
					Signature: [4]byte{2, 1, 1, 1},
					Type:      ObjectType,
					Flags:     0,
				}},
				{header: xlMetaV2VersionHeader{
					VersionID: [16]byte{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1},
					ModTime:   baseTime.Add(30 * time.Minute).UnixNano(),
					Signature: [4]byte{1, 1, 1, 1},

        Map<String, Object> source;
        while ((source = reader.read()) != null) {
            assertTrue(source.get("field1").toString().startsWith("test"));
            valueSet.add(source.get("field1").toString());
            count++;
        }
        assertEquals(num, count);
        assertEquals(num, valueSet.size());
    }

    @Test