Follow these simple steps:

Step 1 - Log-in as applmgr

Step 2 - Go to $INST_TOP/admin/scripts or if you have not setup your application tier environment, then type full path as : /u01/apps/<hostname>/inst/apps/<SID>_<hostname>/admin/scripts

Step 3 - simply run script adapcctl.sh for stopping Apache server first, and then run the same script to start it again.

cd $INST_TOP/admin/scripts

./adapcctl.sh stop

./adapcctl.sh start