code: protected void encode(OutputStream out, ObjectIdentifier extensionId,
          boolean isCritical) throws IOException {
  
         DerOutputStream  tmp = new DerOutputStream();
  
         if (this.extensionValue == null) {
             this.extensionId = extensionId;
             this.critical = isCritical;
             encodeThis();
         }
         super.encode(tmp);
         out.write(tmp.toByteArray());
      }
docs: Write the extension to the DerOutputStream.
  (Also called by the subclass)