I would not bother with Enitity Beans even then. Why teach people to use something the shouldn't be using in the first place? No matter:
Well entity beans represent the OO representation of the data but it is an unnecessary overhead on the memory as the entiy beans
If you need to use the data in your program it will need to be in memory in one form or another. One of the failings of Entity Beans was their heavy weight nature. They were designed with the idea of managing single object in mind, but most application use data in much larger result sets.
I can place the JDBC code directly within the session beans
This is a bad idea, as mentioned earlier.
Further it is said that having entity beans in the appication my application can be scalable.
An Entity Bean is an EJB, so shares the same properties of other EJBs, namely it is a distributable component and hence scalable.