Weblogic by default buffers 8KB worth of access logs hence it only starts printing the entries when this buffer gets full. If you want to see the access log entries straightaway on server start-up then do this,

Step – 1

Login into Weblogic Console,

LOCK & EDIT, Go to HTTP tab,

http-buffer1

Click on Advanced and change 8 -> 0, SAVE &  ACTIVATE.

http-buffer2
Do you want to automate this, use WLST –

wlst-online-01-changeaccesslogbuffer.py