Please consider My Oracle Support note ID 1332498.1, "Undeploying ADF Application Takes > 60 Sec. When Using Application Level JDBC Datasource".
This note is referred to in a comment by Didier on a blog post by Andrejus Baranovskis, "How To Speed Up Application Undeployment in JDeveloper 11g R2" , discussing the same issue.
As symptoms, note 1332498.1 mentions:
"Undeploying/Redeploying an ADF application from the JDeveloper IDE takes more than 60 seconds when using a JDBC Datasource connection (Application level connection, that's the default).
The same takes a few seconds only when using a JDBC URL."
The blog post  ends with the conclusion to always use one of the suggested workarounds "in 11g R2, until it will be fixed", but I wonder when that will be.
Note 1332498.1 refers to bugs
- bug 12686736, "UNDEPLOYING APP TAKES > 60 SEC. WHEN USING APPLICATION LEVEL JDBC DATASOURCE"
which currently has "Status 96 - Closed, Duplicate Bug" and "Base Bug 12796317"
- bug/ER 12796317, "SPEED UP ADF BC REDEPLOYMENT BY CALLING FORCED SHUTDOWN OF WLS DATASOURCE"
which currently has "Status 50 - ER Waiting for Base ER Fix" referring in comments to unpublished bugs 13094312 and 13094341.
Because this looks light it might affect many JDeveloper users, who might prefer to have redeploys work fast out-of-the-box without having to apply workarounds, maybe this JIRA issue can allow others to express their interest in ER 12796317 by simply leaving a comment in this JIRA issue.