Remember that the apps being written for Firefox OS are the first of their kind. They had to write IMAP libraries from bits and pieces of Node libraries because

Remember that the apps being written for Firefox OS are the first of their kind. They had to write IMAP libraries from bits and pieces of Node libraries because no one had ever tried to write an IMAP library for the browser before (of course you couldn't in the past) whereas Java has many mature libraries to choose from. A lot of the complaints surrounding Firefox OS are stuff like this, the Mozilla guys are doing a lot of from-scratch implementations of complicated protocols