How to change oc4jadmin password for Application Server 10gR3

Scenario:

We have a fresh installation of Oracle Application Server 10gR3 (10.1.3.x). We perform following tasks:

1. Create new OC4J instances
2. Deploy Applications on these instances
3. Change password for oc4jadmin user using setup link in Application server console

Problem:

After performing above tasks, when we try to access any OC4J instances other than HOME, the Application Server will deny the access and gives following error on the screen:

Unable to make a connection to OC4J instance instance_name on Application
Server application_server_name. A common cause for this failure is an
authentication error. The administrator password for each OC4J instance in the
Cluster must be the same as the administrator password for the OC4J instance on
which Application Server Control is running.

Reason:

The administrator password for all OC4J instances in the Cluster must be the same as the administrator password for the OC4J instance on which Application Server Control (by default it is HOME instance) is running.
Changing the password through the Setup link does not change the oc4jadmin password used by any remote OC4J instances. A remote OC4J instance is any OC4J instance in a cluster topology that is not hosting the active Application Server Control.
This means that all the OC4J instances should have same oc4jadmin password.

Solution:

Before changing the oc4jadmin password for HOME instance, we must change the oc4jadmin password for remote instances using the following steps:

1. Click on OC4J instance
2. Click on Administration tab
3. Edit sub-task Security Providers under Security task
4. Edit any application name under Application Level Security
5. Click on Realms tab
6. For realm name - jazn.com, click the value under column Users
7. Click on oc4jadmin under User Name column
8. Provide the old Password for oc4jadmin and new password for oc4jadmin and click Apply

Repeat these steps for all the OC4J instances except HOME instance.
After changing the administrator passwords for all OC4J instances, we can then change the oc4jadmin password for HOME instance using setup link on Application server console.

Now all the oc4jadmin passwords are in sync and the application server will be functioning fine.

Oracle Application Server - Basics

This post is for those people who are new to Application Server domain and need simple answers to basic questions i.e., a couple of What is ? kind of questions. Read on...

What is?

1. What is Application Server?

An application server is a software platform that delivers content to the Web. In our case, it is a layer between the clients and the database called middle tier. Common Application logic, business rules, etc are coded in applications in middle tier

2. What is OC4J Instance?

Oracle Containers for Java EE (OC4J) is the core Java EE runtime component of Oracle Application Server.It is a program that serves the J2EE requests of the clients. An OC4J instance is the copy of 1 such program.

3. What is (Middle tier) Application?

The packaged code deployed on the middle tier which contains common application logic, business rules, etc is a Middle tier Application.

4. What is Data Source?

Object to connect to a database. A data source is a Java object and offers a portable, vendor-independent method for creating connections to databases. A data source object's properties are set so that it represents a particular database. An application can use a different database by changing the data source's properties; no change in the application code is required.
The data sources for the OC4J instance are referenced as Java Naming and Directory Interface (JNDI) locations.

5. What is Connection Pooling?

A Data Source (Managed) uses Connection pool to efficiently manage connections. OC4J provides the connection pool feature to increase efficiency by maintaining a cache of physical connections that can be reused. When a client closes a connection, the connection gets placed back into the pool so that another client can use it. A connection pool improves performance and scalability by allowing multiple clients to share a small number of physical connections.

6. What is Deployment?

In Simple terms, Deployment means installing the application. When you deploy application, the Application Server will unpack the deployment file (EAR/WAR/JAR/RAR) and create the directory structures with files, just like they were packed by the developer.

7. What is RMI Port?

Remote Method Invocation (RMI) is a technology that allows an object running in one Java virtual machine (JVM) to invoke methods on an object running in a different Java virtual machine (JVM).

The complete Application Server documentation is available here:

http://download.oracle.com/docs/cd/B31017_01/index.htm

Best Luck :)