EJB stands for Enterprise JavaBean and is a widely-adopted server side component architecture for J2EE. It enables rapid development of mission-critical application that are versatile, reusable and portable across middleware while protecting IT investment and preventing vendor lock-in.
Session Facade is a design pattern to access the Entity bean through local interface than accessing directly. It increases the performance over the network. In this case we call session bean which on turn call entity bean.
EJB technology is the core of J2EE. It enables developers to write reusable and portable server-side business logic for the J2EE platform.
EJB is a specification for J2EE server, not a product; Java beans may be a graphical component in IDE.