Plutext

at the begin of docx4j programm of reading or writing the file there is a kinda 5 sec. delay. Compared to the apache POI which does the same instantly. What kind of problem could that be or its just a docx4j feature?

This delay is caused by the JAXB initialization process. If you use log4j you can see the related "INFO Context - loading Context jc" output at the command line.
Some further research on the internet brings up the fact, that JAXB is the xml binding framework with the slowest initialization process.

I spent some time trying to minimize the delay, to no avail. There are just too many classes in the docx4j/JAXB hierarchy, and there's no way around loading a lot of them before you can do anything. Jason did some work separating some classes into separate JAXB context, presumably in an effort to minimize this delay.

The product where I use docx4j is in a server, so the delay is not too bad.