What is a Java bean? [duplicate]

Answer 1

If you are talking about java-beans and NOT EJB Beans, then here is the explanation...

1. A JavaBean has a constructor that takes no arguments.

2. A JavaBean has a set of properties.

3. A JavaBean has accessor (getXxx, or isXxx for Boolean properties) methods and mutator methods (setXxx) that allow access to its underlying properties.

The 3rd point states a java class with private instance variables and public getter, setter.

eg:

import java.util.Date;

public class User {
    private Date loginDate;
    private String name;
    private String password;

    public User() { }

    public Date getLoginDate() {
        return loginDate;
    }

    public String getName() {
        return name;
    }

    public String getPassword() {
        return password;
    }

    public void setLoginDate(Date loginDate) {
        this.loginDate = loginDate;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public void delete() {
        // code to delete user from database
    }

    public void update() {
        // code to update user in database
    }

    public static User getUser(String name) {
        // code returning a new User object
        // populated from the database
    }
}