By default, allowdupentry in Convergence is set to true. It means you can create many contacts that has the same display name. However, you can set allowdupentry to false at the deployment level.
To set allowdupentry to false
1. Execute the following command:
/opt/SUNWiwc/sbin/iwcadmin -w password -o ab.pstore.allowdupentry -v false
2. Restart the Application Server.
After you set allowdupentry to false, if you try to create a contact with an existing display name, the following error message is displayed: "Save Contact failed."