First of all, for security reason JSF doesn’t allow you to use the GET method for your forms. I didn’t really understand why but this is very (too) restrictive!
Can you imagine Google doing the same thing? We would have the same URL for every search terms http://www.google.co.uk/search instead of something like http://www.google.co.uk/search?hl=en&safe=off&esrch=FT1&q=test&meta=&aq=f&aqi=g10&aql=&oq=&gs_rfai=.
It wouldn’t be very easy to share a search page with a friend if Google was using the POST method.

So the question is how to get around this JSF limitation?

Let’s take a look at how would look our faces-navigation.xml file for a search page:

<navigation-case>
    <from-action>#{searchBean.searchAction}</from-action>
    <from-outcome>success</from-outcome>
    <to-view-id>/search.xhtml</to-view-id>
    <redirect />
</navigation-case>

In this example, all the JSF elements calling the action searchBean.searchAction will be redirected to the search.xhtml page.
But, how are we going to get the search parameters into the URL?

Ideally, it would be great to be able to do something like the following:

<navigation-case>
    <from-action>#{searchBean.searchAction}</from-action>
    <from-outcome>success</from-outcome>
    <to-view-id>/search.xhtml?q=#{param.q}</to-view-id>
    <redirect />
</navigation-case>

This solution would allow us to inject EL expressions into the URL before the page is redirected to the destination page.
In order to do this, we need to create our own view handler and register it to our application.

The code below is the view handler class which also includes some comments:

package com.logikdev.gui.handler;

import javax.el.ExpressionFactory;
import javax.el.ValueExpression;
import javax.faces.application.ViewHandler;
import javax.faces.context.FacesContext;

import com.sun.facelets.FaceletViewHandler;

/**
 * Overrides the Facelet view handler to support EL expressions in URLs.
 * @author Stéphane Moreau
 */
public class DynamicViewHandler extends FaceletViewHandler {

	public DynamicViewHandler(ViewHandler parent) {
		super(parent);
	}

	/* (non-Javadoc)
	 * @see com.sun.facelets.FaceletViewHandler#getActionURL(javax.faces.context.FacesContext, java.lang.String)
	 */
	@Override
	public String getActionURL(FacesContext context, String viewId) {
		String queryString = null;

		// Separate the query string from the URL
		int dotIndex = viewId.lastIndexOf('.');
		int questionMarkIndex = viewId.indexOf('?');
		if (questionMarkIndex != -1) {
			queryString = viewId.substring(questionMarkIndex, dotIndex);
			viewId = viewId.substring(0, questionMarkIndex) + viewId.substring(dotIndex);
		}

		// Call the parent without the query string
		String result = super.getActionURL(context, viewId);

		// Replace the EL expressions in the URL
		ExpressionFactory expressionFactory = context.getApplication().getExpressionFactory();
		ValueExpression valueExpression = expressionFactory.createValueExpression(context.getELContext(), result, String.class);
		result = (String) valueExpression.getValue(context.getELContext());

		// Replace the EL expressions in the query string
		if (queryString != null) {
			valueExpression = expressionFactory.createValueExpression(context.getELContext(), queryString, String.class);
			queryString = (String) valueExpression.getValue(context.getELContext());

	        result += queryString;
		}

	    return result;
	}

}

And the following is the code to put in the faces-config.xml file in order to register the newly created view handler to the application:

<application>
	<variable-resolver>org.springframework.web.jsf.DelegatingVariableResolver</variable-resolver>
	<view-handler>com.logikdev.gui.handler.DynamicViewHandler</view-handler>
</application>

One last thing!
This view handler also has a limitation which I wasn’t able to fix. The file extension has to ALWAYS be placed at the end of the to-view-id URL! The view handler will then put it back before the question mark.
For example:

<navigation-case>
	<from-action>#{searchBean.searchAction}</from-action>
	<from-outcome>success</from-outcome>
	<!-- The extension has to be at the end -->
	<to-view-id>/search?q=#{param.q}.xhtml</to-view-id>
	<redirect />
</navigation-case>

If you perform a search on ‘jsf’ with the above navigation rule, the user will be redirected to the page /search.xhtml?q=jsf.

A lot of tags in RichFaces can AJAX-render elements such as:

<a4j:form>
    <a4j:jsFunction name="updateName" reRender="showname">
        <a4j:actionparam name="param1" assignTo="#{userBean.name}"  />
    </a4j:jsFunction>
</a4j:form>

On the above example, the JavaScript function updateName will AJAX-render the element which has the ID showname.

In some cases, you would have some elements that would AJAX-render without asking them to do so!
I still didn’t figure it out why. (if anybody has an idea, please don’t hesitate to tell me!)

But, I found a way to prevent this!
You simply can add the following attribute to your tag:

limitToList="true"

You even can add it to the tags that don’t have a reRender attribute.
For example:

<a4j:form>
    <a4j:poll id="poll" interval="1000" limitToList="true" />
</a4j:form>

java.lang.ArrayIndexOutOfBoundsException: 5
	at jxl.biff.IndexMapping.getNewIndex(IndexMapping.java:68)
	at jxl.biff.FormattingRecords.rationalize(FormattingRecords.java:388)
	at jxl.write.biff.WritableWorkbookImpl.rationalize(WritableWorkbookImpl.java:988)
	at jxl.write.biff.WritableWorkbookImpl.write(WritableWorkbookImpl.java:692)
	...

It appears that this exception occurs only when you try to generate more than one Excel spreadsheet! How strange is that!
After a bit of investigation, it seems that the problem comes from the use of the static modifier with a jxl.write.WritableFont variable.

I unfortunately don’t have the time to check the JExcelAPI code source to understand the root cause.
So my advice would be: “if you get EXACTLY the same stack trace, simply delete any static modifier you used with the WritableFont variables”.

Let’s take a Java application called MyAddressBook. Its generated war file could be called myaddressbook.war.

By default, when you deploy this web application to Tomcat, the URL to access it will be http://localhost:8080/myaddressbook/. And if you point a domain name such as ‘addressbook.com’ to this server, the URL would be http://addressbook.com/myaddressbook/.

I don’t know for you but I don’t like to systematically have the subfolder ‘myaddressbook’ after my domain. But maybe I am too picky!

The idea is to deploy our application in the Tomcat root context.
You have two ways of doing this:

• Define a ROOT.xml file in your conf/Catalina/localhost folder, or;
• Rename your war file to ROOT.war.

Note that the case is important, it has to be ROOT in UPPERCASE!

Once this is done, you will be able to call your application via the URL http://localhost:8080/
or http://addressbook.com/. Way better!

What you need to do is to monitor your server. But which tools to use? There are so many on the market…

I tested a few of them (Hyperic, Nagios, Zenoss, Cacti, Monitis) but the one I choose is Zabbix. What I like with Zabbix is its price (free ) and the fact that it is easy to configure and very flexible. Indeed, you can monitor anything you want on the machine (CPU, network, disk space, services, etc)!

However, if you also want to monitor your Tomcat application server or even Hibernate Java library, you need some more work.

To monitor Tomcat, you first need to enable JMX Remote. To do so, you can have a look at the official documentation or simply add the following parameters to your Tomcat startup script:

export CATALINA_OPTS='-Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=8999 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false'

Then, I will recommend you to deploy Zapcat JMX Zabbix Bridge in your Tomcat web server. This tool has been developed to simplify the communication between the JMX management API inside Java applications and the Zabbix monitoring tool.

To read the installation instructions for Tomcat, please click on the following link:
http://www.kjkoster.org/zapcat/Tomcat_How_To.html

Finally, if you are using Hibernate in your Java application and would like to monitor it, you have to instantiate and configure a Hibernate MBean (org.jboss.hibernate.jmx.Hibernate) that will be responsible for constructing a Hibernate SessionFactory and exposing it to your application through JNDI.

Here are the lines you need to add to your context XML file:

<bean id="mbeanExporter" class="org.springframework.jmx.export.MBeanExporter" lazy-init="false">
    <property name="server" ref="mbeanServerFactory"/>
    <property name="beans">
        <map>
            <entry key="org.hibernate:type=statistics"  value-ref="hibernateMBean"/>
        </map>
    </property>
</bean>

<bean id="mbeanServerFactory" class="org.springframework.jmx.support.MBeanServerFactoryBean">
    <property name="locateExistingServerIfPossible" value="true"/>
</bean>

<bean id="hibernateMBean" class="org.hibernate.jmx.StatisticsService">
    <property name="sessionFactory" ref="sessionFactory"/>
    <property name="statisticsEnabled" value="true"/>
</bean>