http core 4.2.2 StringEntity 的一个疑问

代码在org.apache.http.entity.StringEntity中。版本4.2.2。
感觉代码和注释不匹配。
同时，没有处理好contentType为null的情况。
4.2.3中无该问题。已经修复。

    /**
     * Creates a StringEntity with the specified content and content type.
     *
     * @param string content to be used. Not {@code null}.
     * @param contentType content type to be used. May be {@code null}, in which case the default
     *   MIME type {@link ContentType#TEXT_PLAIN} is assumed.
     *
     * @throws IllegalArgumentException if the string parameter is null
     *
     * @since 4.2
     */
    public StringEntity(final String string, final ContentType contentType) {
        super();
        if (string == null) {
            throw new IllegalArgumentException("Source string may not be null");
        }
        Charset charset = contentType != null ? contentType.getCharset() : null;
        try {
            this.content = string.getBytes(charset.name());
        } catch (UnsupportedEncodingException ex) {
            // should never happen
            throw new UnsupportedCharsetException(charset.name());
        }
        if (contentType != null) {
            setContentType(contentType.toString());
        }
    }