Oracle ADF Jdeveloper 12c Groovy Expression to Generate Sequence no longer works

Until Jdeveloper 12c for supplying primary key to your entity creation you could simply add a groovy expression in the primary key attribute's default expression like:

(new oracle.jbo.server.SequenceImpl("", adf.object.getDBTransaction())).getSequenceNumber()

However, running the same code in Jdeveloper 12 will throw following runtime exception:

General error during semantic analysis: JBO-25152: Calling the constructor for class oracle.jbo.server.SequenceImpl is not permitted.

Solution:

• Open EO in the source view.
• Search for trustMode="untrusted"
• Change it to trustMode="trusted"

This should work now.