The JavaBean specification defines a set of rules / conventions that, if complied with, make a plain old Java object (POJO) a valid JavaBean. The purpose of that is to turn a Java objects into components that can be easily shared and plugged / composed into applications. What you seem to be focussing on is only one aspect of the JavaBean specification, which are properties (not to be confused with the language construct that Java does not provide), but the JavaBean specification also allows for public methods besides the methods related to properties. There are also the the event and persistence (serialization) facilities.
The EJB specification is also a set of rules that turn Java objects into components, but the key difference is that these components must be managed by an application server and the specification is far more extensive, covering the component lifecycle, transactions, concurrency, scheduling, naming, remoting, security and more.
Build a man a fire, and he'll be warm for a day. Set a man on fire, and he'll be warm for the rest of his life.
subject: What we can write in Java Beans except setter and getter?