Failed to get file status with empty MIME type

[qinlan1021]

/**
 * Get file status without file stream.
 *
 * @param fileId File id.
 * @return File status.
 * @throws IOException Http connection is fail or server response within some error message.
 */
public FileHandleStatus getFileStatus(String fileId) throws IOException {
    final String targetUrl = getTargetUrl(fileId);
    HeaderResponse headerResponse = volumeWrapper.getFileStatusHeader(targetUrl, fileId);
    try {
        return new FileHandleStatus(fileId,
                headerDateFormat.parse(headerResponse.getLastHeader("Last-Modified").getValue()).getTime(),
                headerResponse.getLastHeader("Content-Disposition").getValue()
                        .substring(10, headerResponse.getLastHeader("Content-Disposition").getValue().length() - 1),
                headerResponse.getLastHeader("Content-Type").getValue(),
                Long.parseLong(headerResponse.getLastHeader("Content-Length").getValue()));
    } catch (ParseException e) {
        throw new SeaweedfsException("Could not parse last modified time [" +
                headerResponse.getLastHeader("Last-Modified").getValue() + "] to long value");
    }
}

headerResponse.getLastHeader("Content-Type").getValue() Raises java.lang.NullPointerException when the MIME type is empty in file.