Zosden, thanks for the recommendation, I always love C++ and VB, but we need to go the direction the company decided.
Sukatoa, thanks for the advise, I will try to improve it as you recommend as much as possible. Regarding the implementation, I export the project to a Jar file then run it from DOS Command (which I built a .BAT file to run it).
Heap size does not matter much to this project, I mean, I increase to 500M to start and 500M max, I checked the CPU usage, it only used in an average of 40M-50M. I also asked the DBA to trace it run, he said the my Java thread took an avarage of quick 5-10 ms to execute when retrieved objects (files) from Content Manager.
My boss said if it took 10 ms/6 documents to be retrieved from CM, total of 51000 == 510000 ms == 5100 sec == 85 minutes, why it ran for more than 12 hours. I said it need to be saved to the F: drive too, and this one I cannot prove how long does it takes to save a file to a drive (the 6 documents who repeatingly retrieved and copied over has an average of 200Kb each). And it also depends on the network traffic, and the number of access to F: drive from other users.