See the release notes for a list of databases you can use with Business Components for Java.
For deployment, you need to meet some requirements in addition to the normal JDeveloper requirements:
To deploy to an Oracle 8i database, make sure you match the JDK to the JVM in your version of 8i. You can switch the JDK right before you deploy, if needed.
If you want to deploy to your development computer (it runs both JDeveloper and the database), you need at least 256 MB of RAM, and the database's Java pool size must be at least 50 MB (in init.ora, java_pool_size=50000000).
Your connections must be associated with a user that has appropriate Java2 Permissions.