Reset the oc4jadmin password using the following procedure while you are logged in as the user who installed the Oracle Application Server instance:
 1. Stop OC4J and the Application Server Control.
$ORACLE_HOME/opmn/bin/opmnctl stopall
  
 2. Locate and open the following file in a text editor:
$ORACLE_HOME/j2ee/home/config/system-jazn-data.xml
  
3. Locate the line that defines the credentials property for the oc4jadmin user.
jazn.com
        .
         .
         .
           oc4jadmin
              OC4J Administrator
              OC4J Administrator
                {903}4L50lHJWIFGwLgHXTub7eYK9e0AnWLUH
         
4. Replace the existing encrypted password with the new password.
    Be sure to prefix the password with an exclamation point (!). For example:
!mynewpassword123