Jsf datatable writes my data 3 times - jsf

Question

I am trying to learn JSF and i have a problem with datatable.
I get datas from database and add them to my list and try to show them in my page. It write datas 3 times. Why is it? Here is my code...
here is related part of bean..
public ArrayList<videos> getVideoss() {
Connection con1 = null;
PreparedStatement pst1 = null;
ResultSet rs1 = null;
String url1 = "jdbc:postgresql://localhost:5432/db";
String user1 = "postgres";
String password11 = "123";
try {
Class.forName("org.postgresql.Driver");
con1 = DriverManager.getConnection(url1, user1, password11);
pst1 = con1
.prepareStatement("SELECT video_name FROM videos WHERE video_course = '"
+ selectedCourse + "';");
rs1 = pst1.executeQuery();
while (rs1.next()) {
videoss.add(new videos(rs1.getString(1)));
}
System.out.println(videoss.size());
.....
xhtml file
<h:dataTable value="#{videoSearch.videoss}" var="videos">
<h:column>
<f:facet name="header">Video Name</f:facet>
#{videos.videoName}
</h:column>
</h:dataTable>
when i look the size of the list it goes like 6 , 12 , 18.. but it should be 6..
Thanks for your support..

Answer 1

As I commented, you are recreting the list every time the getter is called, so the list is growing because you are not clearing it anywhere. Here is a better way to do it :
// Will be called only one time
#PostConstruct
public init()
{
Connection con1 = null;
PreparedStatement pst1 = null;
ResultSet rs1 = null;
String url1 = "jdbc:postgresql://localhost:5432/Thesis";
String user1 = "postgres";
String password11 = "123";
videoss = new ArrayList();
try
{
Class.forName("org.postgresql.Driver");
con1 = DriverManager.getConnection(url1, user1, password11);
pst1 = con1.prepareStatement("SELECT video_name FROM videos WHERE video_course = '" + selectedCourse + "';");
rs1 = pst1.executeQuery();
while (rs1.next())
{
videoss.add(new videos(rs1.getString(1)));
}
System.out.println(videoss.size());
//.....
}
catch(Excepption e)
{
e.printStackTrace();
}
}
public ArrayList<videos> getVideoss()
{
return videoss;
}