Seventeen Stars

synchonization job and pre/post job

hi all,
I've got an apllication running a "main job" which pilot some subjob !
But before main job 's running , my app use a Pre-job
Any problem until now, except this morning where the "pre-job" was trying to copy a file that wasn' t there Smiley Happy !
And it's only possible if "main job " has running before !
Is it possible or my algorytmn has something wong ?
How pre and post job are synchronized in Talend (with wait notify and synchonized object method in java) ?
Is this way (pre main post JOB ) is a secured way to synchronized my app ?,
A lot of questions in a single post Smiley Happy but I need to be sure about those components and the way it 's running !
hopefully this app 's still in Dev ...

thanks for your help
"Talend Open Studio"
Version: 3.1.4
Build id: r29781-20090916-0502