code: private String getString(DerValue attribute) throws IOException {
          if (attribute == null)
              return null;
          String  value = attribute.getAsString();
  
          if (value == null)
              throw new IOException("not a DER string encoding, "
                      + attribute.tag);
          else
              return value;
      }
docs: /*
  Returns the name component as a Java string, regardless of its
  encoding restrictions.