> Sorry but where can I get it? Is there a repository?

Sure, see here: http://sourceforge.net/projects/firebird/develop, module name
is "client-java".

To get sources you simply do:

cvs -d:pserver:anonymous@...:/cvsroot/firebird login
cvs -d:pserver:anonymous@...:/cvsroot/firebird co -P
client-java

Then you have build.bat/build.sh, which builds the sources.

Roman