While reading that pile of code I couldn't help parsing it as Java, although syntactically it could be a wide variety of languages.

Are there any other languages' libraries with complicated designs like that one or is this a problem specific to Java?

Just to give an example, this is a snippet of code I had to write dozens of times in a college project using the javax.xml.soap library to create a simple soap message with a tag on it:

  MessageFactory mf = MessageFactory.newInstance();
  SOAPMessage soapMessage = mf.createMessage();
  SOAPPart soapPart = soapMessage.getSOAPPart();
  SOAPEnvelope soapEnvelope = soapPart.getEnvelope();
  SOAPBody soapBody = soapEnvelope.getBody();
  Name name = soapEnvelope.createName("HelloWorld", "hw", "");
  SOAPElement element = soapBody.addChildElement(name);
  element.addTextNode( "hello text message" );

It's not exactly the same issue has in the example on the blog post, but I think it also represents something that could be a lot simpler/shorter.