I'm still seeing this problem (Database 'PUB_feed_libx_dot_editions_at_gmail...' is currently opened by another client). 

I was able to connect via org.basex.BaseXClient to the database and saw, via 'SHOW SESSIONS', that the database in question was listed like so:

> SHOW SESSIONS
3 session(s):
- admin [127.0.0.1:35515]: ts_20120725_dot_213235_dot_723_feed_libx_dot_editions_at_gmail_dot_com_core
- admin [127.0.0.1:37210]
- admin [127.0.0.1:44610]: PUB_feed_libx_dot_editions_at_gmail_dot_com_core

From the code in Sessions.java/Context.java, I inferred that the db in question ('PUB_feed_libx_dot_editions_at_gmail_dot_com_core') was the 'current data reference' of session :44610.

How can that be?

As a reminder, I'm not using any 'OPEN' commands...

So I've examined the logs when this db became the 'current' database of that session, and that, apparently, happened when it was created: 

13:58:21.113    [127.0.0.1:44610]: ts_20120725_dot_135820_dot_723_feed_libx_dot_editions_at_gmail_dot_com_core  CREATE DB PUB_feed_libx_dot_editions_at_gmail_dot_com_core [...]
13:58:21.164    [127.0.0.1:44610]: PUB_feed_libx_dot_editions_at_gmail_dot_com_core OK  50.95 ms

Is this an undocumented side-effect of 'CREATE DB'?  

Is it necessary to follow every 'CREATE DB...' statement with a 'CLOSE' statement to avoid that the session in which the db was created keeps it open? It is not mentioned here: http://docs.basex.org/wiki/Commands#CREATE_DB

If true, I find this rather unusual - and certainly unexpected - it would be as if a 'CREATE DATABASE' statement in SQL automatically issued a 'USE'... command.

 - Godmar