@Override
    public String toString() {
      return "CharMatcher.javaUpperCase()";
    }
  }

  /** Implementation of {@link #javaLowerCase()}. */
  private static final class JavaLowerCase extends CharMatcher {

    static final CharMatcher INSTANCE = new JavaLowerCase();

    @Override
    public boolean matches(char c) {
      return Character.isLowerCase(c);
    }

    @Override