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    <p>They often just represents real world data. Here's a simple example of a Javabean:</p> <pre><code>public class User implements java.io.Serializable { // Properties. private Long id; private String name; private Date birthdate; // Getters. public Long getId() { return id; } public String getName() { return name; } public Date getBirthdate() { return birthdate; } // Setters. public void setId(Long id) { this.id = id; } public void setName(String name) { this.name = name; } public void setBirthdate(Date birthdate) { this.birthdate = birthdate; } // Important java.lang.Object overrides. public boolean equals(Object other) { return (other instanceof User) &amp;&amp; (id != null) ? id.equals(((User) other).id) : (other == this); } public int hashCode() { return (id != null) ? (getClass().hashCode() + id.hashCode()) : super.hashCode(); } public String toString() { return String.format("User[id=%d,name=%s,birthdate=%d]", id, name, birthdate); } } </code></pre> <p>Implementing <code>Serializable</code> is not per se mandatory, but very useful if you'd like to be able to persist or transfer Javabeans outside Java's memory, e.g. in harddisk or over network. </p> <p>In for example a DAO class you can use it to create a list of users wherein you <strong>store</strong> the data of the <code>user</code> table in the database:</p> <pre><code>List&lt;User&gt; users = new ArrayList&lt;User&gt;(); while (resultSet.next()) { User user = new User(); user.setId(resultSet.getLong("id")); user.setName(resultSet.getString("name")); user.setBirthdate(resultSet.getDate("birthdate")); users.add(user); } return users; </code></pre> <p>In for example a Servlet class you can use it to <strong>transfer</strong> data from the database to the UI:</p> <pre><code>protected void doGet(HttpServletRequest request, HttpServletResponse response) { List&lt;User&gt; users = userDAO.list(); request.setAttribute("users", users); request.getRequestDispatcher("users.jsp").forward(request, response); } </code></pre> <p>In for example a JSP page you can <strong>access</strong> it by <a href="http://docs.oracle.com/javaee/1.4/tutorial/doc/JSPIntro7.html" rel="noreferrer">EL</a>, which follows the Javabean conventions, to display the data:</p> <pre class="lang-html prettyprint-override"><code>&lt;table&gt; &lt;tr&gt; &lt;th&gt;ID&lt;/th&gt; &lt;th&gt;Name&lt;/th&gt; &lt;th&gt;Birthdate&lt;/th&gt; &lt;/tr&gt; &lt;c:forEach items="${users}" var="user"&gt; &lt;tr&gt; &lt;td&gt;${user.id}&lt;/td&gt; &lt;td&gt;&lt;c:out value="${user.name}" /&gt;&lt;/td&gt; &lt;td&gt;&lt;fmt:formatDate value="${user.birthdate}" pattern="yyyy-MM-dd" /&gt;&lt;/td&gt; &lt;/tr&gt; &lt;/c:forEach&gt; &lt;/table&gt; </code></pre> <p>Does it make sense? You see, it's kind of a <strong>convention</strong> which you can use everywhere to <em>store</em>, <em>transfer</em> and <em>access</em> data.</p> <h3>See also:</h3> <ul> <li><a href="http://www.oracle.com/technetwork/java/javase/documentation/spec-136004.html" rel="noreferrer">JavaBeans specification</a></li> </ul>
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    1. CONice explanation, and typically thanks for this **Implementing Serializable is not per se mandatory, but very useful if you'd like to be able to persist or transfer Javabeans outside Java's memory, e.g. in harddisk or over network.**
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