* {@code b} have no common prefix, returns the empty string.
   *
   * @since 11.0
   */
  public static String commonPrefix(CharSequence a, CharSequence b) {
    checkNotNull(a);
    checkNotNull(b);

    int maxPrefixLength = min(a.length(), b.length());
    int p = 0;
    while (p < maxPrefixLength && a.charAt(p) == b.charAt(p)) {
      p++;

      checkNotNull(sequence);
      return "";
    }

    @Override
    public String replaceFrom(CharSequence sequence, char replacement) {
      char[] array = new char[sequence.length()];
      Arrays.fill(array, replacement);
      return new String(array);
    }

    @Override
    public String replaceFrom(CharSequence sequence, CharSequence replacement) {

    checkNotClosed();
    target.append(c);
    return this;
  }

  @Override
  public Writer append(@Nullable CharSequence charSeq) throws IOException {
    checkNotClosed();
    target.append(charSeq);
    return this;
  }

  @Override
  public Writer append(@Nullable CharSequence charSeq, int start, int end) throws IOException {
    checkNotClosed();
    target.append(charSeq, start, end);
    return this;

   * time and space.
   *
   * @throws IllegalArgumentException if {@code sequence} contains ill-formed UTF-16 (unpaired
   *     surrogates)
   */
  public static int encodedLength(CharSequence sequence) {
    // Warning to maintainers: this implementation is highly optimized.
    int utf16Length = sequence.length();
    int utf8Length = utf16Length;
    int i = 0;

    // This loop optimizes for pure ASCII.

import jakarta.validation.ConstraintValidatorContext;

/**
 * Validator implementation for the CustomSize constraint.
 */
public class CustomSizeValidator implements ConstraintValidator<CustomSize, CharSequence> {

    /**
     * Default constructor.
     */
    public CustomSizeValidator() {
        // Empty constructor
    }

    private int min = 0;
    private int max = Integer.MAX_VALUE;

   * @param builder A map builder to which all entries will be added.
   * @return The number of characters consumed from {@code encoded}.
   */
  private static int doParseTrieToBuilder(
      Deque<CharSequence> stack,
      CharSequence encoded,
      int start,
      ImmutableMap.Builder<String, PublicSuffixType> builder) {

    int encodedLen = encoded.length();
    int idx = start;
    char c = '\0';

  }

  public void testGetGenericSuperclass_wildcard_boundIsInterface() {
    assertNull(TypeToken.of(Types.subtypeOf(CharSequence.class)).getGenericSuperclass());
    assertEquals(
        new TypeToken<CharSequence[]>() {},
        TypeToken.of(Types.subtypeOf(CharSequence[].class)).getGenericSuperclass());
  }

  public <T> void testGetGenericInterfaces_typeVariable_unbounded() {

  }

  @GwtIncompatible // ObjectArrays.concat(Object[], Object[], Class)
  public void testConcatWithMoreGeneralType() {
    CharSequence[] result = ObjectArrays.concat(new String[0], new String[0], CharSequence.class);
    assertEquals(CharSequence[].class, result.getClass());
  }

  public void testToArrayImpl1() {
    doTestToArrayImpl1(new ArrayList<Integer>());

  public void testContainsPattern_apply() {
    Predicate<CharSequence> isFoobar = Predicates.containsPattern("^Fo.*o.*bar$");
    assertTrue(isFoobar.apply("Foxyzoabcbar"));
    assertFalse(isFoobar.apply("Foobarx"));
  }

  @GwtIncompatible // Predicates.containsPattern
  public void testContains_apply() {
    Predicate<CharSequence> isFoobar = Predicates.contains(Pattern.compile("^Fo.*o.*bar$"));

  }

  public void testGetGenericSuperclass_wildcard_boundIsInterface() {
    assertNull(TypeToken.of(Types.subtypeOf(CharSequence.class)).getGenericSuperclass());
    assertEquals(
        new TypeToken<CharSequence[]>() {},
        TypeToken.of(Types.subtypeOf(CharSequence[].class)).getGenericSuperclass());
  }

  public <T> void testGetGenericInterfaces_typeVariable_unbounded() {