JavaBeans is the concept of encapsulating several objects into one single object and they are the reusable components for Java. They set aside to access the properties using setter and getter methods. They do have 0-argument constructor. The events, properties and methods of another application can be controlled using java bean. A bean can register to obtain, receive events and can create events which is in other objects. To assist configure a java bean auxiliary software is provided. The settings of bean could be saved in storage and restored whenever required.
A class with null constructor is treated to be instantiated in an invalid state. If that class is instantiated by a developer manually then they may come to the conclusion that the class has been improperly instantiated. The compiler fails to detect such problems. The class consists of public default constructor. Just by editing and activation framework it can be easily instantiated. Property of the class should be accessible using set, get, is and other methods. This permits easy inspection and updating of java bean state within the frameworks. The class should always be serializable. For this major reason Java bean is used widely.