Can a JavaBean have methods besides getters and setters?

Question

According to definitions I find in the internet a JavaBean is a Java class that satisfies these conditions:

All instance attributes are private
All instance attributes have public getters and setters
The class has a parameterless constructor
The class implements the Serializable interface

What I would like to know is that if I add method to a Javabean can we still call it a Javabean?

For exemple can we say that the following class is a JavaBean?

public class Person implements Serializable {
    private String name;
    public Person(){}
    public String getName(){...}
    public void setName(String name){...}
    public void sayHello(){}
}

What gave you an idea that it can't? If you give a car (vehicle) an ability to fly/sail/drive itself would it stop being a car/vehicle? — Germann Arlington, Apr 03 '14 at 15:43
why not? if you add methods, the class still satisfies the conditions:) — hsluo, Apr 03 '14 at 15:48

score 11 · Accepted Answer · answered Apr 03 '14 at 15:53

Yes, Java Beans can definitely have behavior. Java Bean classes without additional methods have very limited applicability, because they encapsulate data devoid of useful behavior.

Oracle mentions this in one of their tutorials on Java Beans:

A bean's methods are the things it can do. Any public method that is not part of a property definition is a bean method. When you use a bean in the context of a builder tool like NetBeans, you can use a bean's methods as part of your application. For example, you could wire a button press to call one of your bean's methods.

score 3 · Answer 2 · edited Mar 17 '17 at 07:32

Yes, java beans can have additional functionality. The convention was introduced to access properties in a structured way and add functionality like vetoing. It is used for example for GUI components in swing, where the bean mechanism is used to configure the GUI elements. Especially in GUI editors there was the need to dynamically access unknown properties. And of course, these GUI components have lots of functionalities. What you get if you restrict to your set of conditions is a DTO (data transfer object), that only transports data but has no additional functions.

Can a JavaBean have methods besides getters and setters?

2 Answers2