Error: [ADF security error] The method getDBTransaction on class oracle.jbo.server.EntityImpl is not permitted

[JDev 12.2.1.0]

I have created an EntityObject from database table and assigned an expression to its key attribute to get the value from a database sequance (See this post to know how to assign a db sequence to a property in entity object ). But while building the project, I got the below error.

Error(11,53): [Static type checking] - [ADF security error] The method getDBTransaction on class oracle.jbo.server.EntityImpl is not permitted.

 @ line 11, column 53. Locations.bcs D:\Application2\Model\src\model Model.jpr

Which means that the entity is not trusted the expression changes. To avoid this issue,

• Go to the source of the entity object xml file 
• Search for the tag "TransientExpression"
• Check the value of the attribute "trustMode"
• If it is "untrusted", change it to "trusted"
• Now rebuild the project

The above change solved my issue .