Seems like a rash of questions recently about how to reset Oracle Application Server/OC4J's administrator password and for whatever reason Google doesn't index our doc (as per the feedback below, due to our robot.txt disallowing this - I don't know why this is the policy) and as a result isn't finding the entry in our doc on how to do this here:
Reproduced in its entirety below  and hopefully this will help Google point people to the right information.
One of the "tricks" you have to be aware of when doing this is that if you are using Application Server Control to manage a cluster of OC4J's, there is a default assumption that all the OC4J's use the same administrator password (you can override) - if you are doing this, step 5 of the instructions, which talks about removing the ASControl cached security file (passwords encrypted!) to re-enable cluster management, is important to heed when you do this.
oc4jadmin password using the following procedure while you are logged in as the user who installed the Oracle Application Server instance:
Stop OC4J and the Application Server Control.
Enter the following command in the Oracle home of the application server instance:
(UNIX) ORACLE_HOME/opmn/bin/opmnctl stopproc ias-component=OC4J
(Windows) ORACLE_HOME\opmn\bin\opmnctl stopproc ias-component=OC4J
Locate the line that defines the credentials property for the oc4j
The following example shows the section of
system-jazn-data.xmlwith the encrypted
credentialsentry in boldface type:
Replace the existing encrypted password with the new password.
Be sure to prefix the password with an exclamation point (!). For example:
Must contain at least five characters, but not more than 30 characters.
Must begin with an alphabetic character. It cannot begin with a number, the underscore (_), the dollar sign ($), or the number sign (#).
At least one of the characters must be a number.
Can contain only the following characters; numbers, letters, and the following special characters: US dollar sign ($), number sign (#), or underscore (_).
Cannot contain any Oracle reserved words, such as VARCHAR.
See Also:"The oc4jadmin User and Restrictions on its Password" in the Oracle Application Server Installation Guide
Delete cached password data by deleting the contents of the following directory:
Start OC4J and the Application Server Control.
After the restart, the Application Server Control will use your new Administrator (
oc4jadmin) password, which will be stored in encrypted format within the