Is there an up-to-date Java API for Skype 4.0? I’d need a simple bot that creates a chat and follows discussion.
If there isn’t a Java API, what ways are there to send Skype commands in Java?
Also, am I allowed to use public Skype for that, or do I need to have my own Jabber server?
You can use the Skype4Java wrapper for the Skype API
Skype itself is a proprietary protocol – it doesnt use Jabber. The only way to interface with skype at present is through a plugin for their client, using the API as mentioned.
I believe the API also works for version 4.