So there has been some noise from Sun about how Google AppEngine is evil because it’s not supporting the complete set of classes in the JRE. I’m sorry Sun – I’m a Java programmer, and I think that argument is shit. I’d much prefer a partial Java implementation with well defined limitations than PHP, or Python or Ruby.
AFAIK, no one has posted a list of classes missing. I can’t be bothered doing that either, but I did manually take a look at package level. Here’s it looks like GAE/J is missing:
From that list, I’d like to see javax.activation, javax.management and the remaining javax.xml.* and maybe javax.tools packages supported. The rest really don’t seem at all relevant to the AppEngine environment.