A Java Bean is a java class that should follow following conventions:
It should have a no-arg constructor.
It should be Serializable.
It should provide methods to set and get the values of the properties, known as getter and setter methods.
Why use Java Bean?
According to Java white paper, it is a reusable software component. A bean encapsulates many objects into one object, so we can access this object from multiple places. Moreover, it provides the easy maintenance.