Notes tmp dir

I have lotus notes client 8.5.1 installed on linux.I have a sample prgm which does the following -

NotesThread.sinitThread();

Session s = NotesFactory.createSession(name, user, password);

Database db = s.getDatabase(null,nsfname);

// enumerate folders/views

Vector folders = null;

folders = db.getViews();

s.recycle();

NotesThread.stermThread();

Lets say I run this program as “user1”, then a folder is created in the home directory of user1 called “lotus” i.e →

$ls /home/user1/lotus/notes/data/

binary.gif fault_recovery.log graphic.gif IDB36326.DTF IDB94742.DTF image.gif movie.gif ~notetp2.reg sound.gif unknown.gif

browser.cnf folder.gif help.dir IDB64171.DTF IDB95527.DTF ini.nbf mq.nbf pid.nbf text.gif

error.gif frstrings.dat IBM_TECHNICAL_SUPPORT IDB77948.DTF IDB98991.DTF link.gif notes.ini shm.nbf ticket.idt

Why is this folder created ? When should it be cleaned and how ?