problem in getInitParameterNames() method of ServletConfig

[Joshua Antony]

A part of my deployment descriptor is as below.

<servlet>
<servlet-name>GetJar</servlet-name>
<servlet-class>ReadingJarFile</servlet-class>
<load-on-startup>1</load-on-startup>
<init-param>
<param-name>name1</param-name>
<param-value>value2</param-value>
</init-param>
<init-param>
<param-name>name2</param-name>
<param-value>value1</param-value>
</init-param>
</servlet>

Although 2 parameters are mentioned here but during the execution of the following code:

PrintWriter writer = response.getWriter();
ServletConfig config = getServletConfig();
Enumeration initParameters = config.getInitParameterNames();
while(initParameters.hasMoreElements())
{
writer.write((String)initParameters.nextElement()+"\n");
}
writer.flush();

I get output as name2 name1 .
Why is line seperator not taking any effect. And why is the order in the output different I mean name2 and then name1 and not the other way round.

Kind Regards,
Joshua

[Paul Anilprem]

Originally posted by joshua antony:

I get output as name2 name1 .
Why is line seperator not taking any effect.

Do "view source" on the browser page. You should see two lines. In HTML \n is just a space. To display a new line, use <br>.

Originally posted by joshua antony:

And why is the order in the output different I mean name2 and then name1 and not the other way round.

Enumeration returns elements in the order supplied to it by the underlying Collection. The servlet specification makes no statements about that Collection. It does return the elements is some order, just not in the order you expected.

My guess is that it uses some HashMap to store paramname - paramvalue pairs and returns a Set (probably a HashSet) of parameter names using map.keySet(), which in turn is the underlying collection for the Enumeration. If you really want to know the algorithm which is used by HashSet for returning elements, you have to look at HashSet source because the API doesn't specify (and thus, guarantee) it.

[Christophe Verré]

Why is line seperator not taking any effect.

Are you outputting into the web browser ? If so, maybe you should try the "br" tag instead.

And why is the order in the output different I mean name2 and then name1 and not the other way round.

It's not specified anywhere that the order of the initparams will be the same.
Who cares about the order anyway ?

[Marc Peabody]

Right click and select View Source in your browser to see the lines separated. The browser simply treats the break as a single space when it renders content to the screen.

[Christophe Verré]

Wow, three simultaneous posts

[Joshua Antony]

Thanks all for your replies.
I got the point.

Kind Regards,
Joshua