How to start Web logic Admin Server?

Go to domain your domain directory
cd $ORACLE_HOME/user_projects/domains//bin
$ ./startWebLogic.sh

First got to your domain/bin and run setDomainEnv.sh, then run below commands
$ java -Dweblogic.Name= -Dweblogic.ConfigFile=config.xml -Dweblogic.RootDirectory = weblogic.Server

Example - 
java -Dweblogic.Name=JJTU_AdminServer -Dweblogic.ConfigFile= C:\Oracle\Middleware2\user_pr ojects\domains\JJTU_Domain1\config\config.xml -Dweblogic.RootDirectory = C:\Oracle\Middleware2\user _projects\domains\JJTU_Domain1 weblogic.Server