- No bothering with config files (educational purposes) => account/password, admin hardcoded
- Also, since educational purposes - public domain! (you'd modify an existing source to learn jabber anyway)
- Uses apache's java HTTP client library - a simple auth to twitter and a POST
- User binds twitter account by sending a register <twitterusername> <twitterpassword> message to the bot.
- Doesn't save its state (bot stops => twitter account data lost)- could implement with Serializable markerinterface
- Doesn't use session-handling: logs into twitter every time; normally, twitter api would need to remember session cookies for each user/pass and trying to simply post the status variable, and if fails (with errorcode 403 presumably), relogin and store session cookies again
- No multithreading - if twitter is slow, the bot stops responding while doing HTTP query. Normally, at least two threads (one for the twitter api and one for the XMPP connection) should be used.
- No selective presence/multiple resources/etc - load balancing could be done with bots with same accounts but different resources and probably selective presence/invisibility
You can download java sourcecode here.
The needed libraries - which aren't in public domain(!) - are boundled too.