JavaBean is a reusable component written in Java language. To write a JavaBean, the class must be concrete and public, and have a parameterless constructor. JavaBean exposes the member properties of the internal domain by providing a common method that conforms to the consistent design pattern, and obtains the member properties by using set and get methods. As we all know, property names conform to this pattern, and other Java classes can discover and manipulate the properties of these JavaBeans through introspection mechanism.