* @return 最初の要素
     */
    public E getFirst() {
        if (isEmpty()) {
            throw new NoSuchElementException();
        }
        return getFirstEntry().element;
    }

    /**
     * 最後の要素を返します。
     *
     * @return 最後の要素
     */
    public E getLast() {
        if (isEmpty()) {
            throw new NoSuchElementException();
        }
        return getLastEntry().element;
    }

    /**

            throw new InvalidQueryRegisteredException(msg);
        }
    }

    protected void checkEsInvalidQueryCollection(String name, Collection<?> values) {
        if (values == null || values.isEmpty()) {
            String msg = "Cannot register null or empty query collection: name=" + name + " values=" + values;
            throw new InvalidQueryRegisteredException(msg);
        }

            throw new InvalidQueryRegisteredException(msg);
        }
    }

    protected void checkEsInvalidQueryCollection(String name, Collection<?> values) {
        if (values == null || values.isEmpty()) {
            String msg = "Cannot register null or empty query collection: name=" + name + " values=" + values;
            throw new InvalidQueryRegisteredException(msg);
        }

        assertArgumentNotNull("field", field);

        try {
            return (T) field.get(target);
        } catch (final IllegalAccessException ex) {
            throw new IllegalAccessRuntimeException(field.getDeclaringClass(), ex);
        }
    }

    /**
     * {@literal static}な {@link Field}の値をintとして取得します。
     *
     * @param field

                    if (!Files.isDirectory(topDirectory)) {
                        throw new ParserException("Directory " + topDirectory
                                + " extracted from the -f/--file command-line argument " + arg + " does not exist");
                    }
                } else {
                    throw new ParserException(

    @Override
    public String toString() {
      return "CountingSupplier";
    }
  }

  static class ThrowingSupplier implements Supplier<Integer> {
    @Override
    public Integer get() {
      throw new NullPointerException();
    }
  }

  static class SerializableCountingSupplier extends CountingSupplier implements Serializable {
    private static final long serialVersionUID = 0L;
  }

    @Override
    public String toString() {
      return "CountingSupplier";
    }
  }

  static class ThrowingSupplier implements Supplier<Integer> {
    @Override
    public Integer get() {
      throw new NullPointerException();
    }
  }

  static class SerializableCountingSupplier extends CountingSupplier implements Serializable {
    private static final long serialVersionUID = 0L;
  }

  }

  private void assertSetCountNegativeOldCount() {
    try {
      getMultiset().setCount(e3(), -1, 1);
      fail("calling setCount() with a negative oldCount should throw IllegalArgumentException");
    } catch (IllegalArgumentException expected) {
    }
  }

  // Negative oldCount.

  @CollectionFeature.Require(SUPPORTS_ADD)

  public void testRemoveIf_unsupportedEmptyCollection() {
    try {
      assertFalse(
          "removeIf(Predicate) should return false or throw " + "UnsupportedOperationException",
          collection.removeIf(
              x -> {
                throw new AssertionError("predicate should never be called");
              }));
    } catch (UnsupportedOperationException tolerated) {
    }
    expectUnchanged();
  }

   */
  static void assertBasicUrlEscaperExceptPercent(UnicodeEscaper e) {
    // URL escapers should throw null pointer exceptions for null input
    try {
      e.escape((String) null);
      fail("Escaping null string should throw exception");
    } catch (NullPointerException x) {
      // pass
    }

    // All URL escapers should leave 0-9, A-Z, a-z unescaped