Nicolas Fränkel

Tomcat manages application security through the concept of realm. A realm is a coherent package of name password pairs that identify valid users for a web application. Tomcat’s default realm is MemoryRealm. This realm reads the famous conf/tomcat-users.xml file and uses it check for name password pair validity. Tomcat also provides realms to check against pairs stored in a database, either through a direct connection, or through a configured datasource. The main disadvantage of these all

Taglibs are wonderful components available since J2EE 1.3. They enable you, as developer: to refrain from using too much scriptlets (free-form Java code) in your Java Server Pages,to have a library of reusable components that can be distributed to all your projects. Both are very important in the enterprise as of now. For example, as an architect, you can disallow the use of scriptlets altogether and then provide taglibs to restrain what can be done on the page. Such policies are not uncommon a

[…​] coupling (or dependency) is the degree to which each program module relies on each one of the other modules. — Wikipedia http://en.wikipedia.org/wiki/Coupling_(computer_science) In object-oriented programming, removing dependencies is done by using interface. Thus, if class A is dependent on class B, we introduce interface C, which is implemented by B. Now A depends on C  (see below). This first step in decoupling is called programming by interface. Anyway, we sti

1. Generalities Web applications have several advantages over traditional client server applications: since business code comes from a unique server (forget clustering here), they are always up-to-date. Moreover, deployment of a new version is only a matter of minutes. They have one big drawback, though. Since HTML code is sent through the network, responsiveness is generally much less than that of traditional applications. The responsiveness of an interactive system describes how quickly

With new JEE 5 standard has come the EJB3 specifications. From an historical point of view, EJBs come into 3 different flavors: (i) Entity for persistence, (ii) Session for business logic and (iii) Message-Driven for listeners. Entity EJB are the most time-consuming to develop in their 2.1 version. Apart from the inherent complexity of EJB (local and remote interfaces, homes), developing an EJB 2 is error-prone because of the mapping mechanism. All in all, EJB 2 development really needs a very sp

Noticed anything different on this blog? No? Yet, I upgraded WordPress from version 2.5 to version 2.7.1. Since you had no problems viewing this post, we can safely admit the upgrade process was entirely successful. The upgrade process is very simple since WordPress is developed in PHP. Just copy (and sometimes overwrite) the contents of the wordpress folder to your webserver and presto, you got the new version. I must admit I was a little afraid something would go wrong…​ And what

If like me you’re traveling often, and develop while doing so, you don’t want to waste time. Every laptop nowadays has a wifi interface: problem is finding the hotspot, not an easy task on a plane or on a train. Once, I used to download and save each and every Javadoc of Java, JEE and the various OpenSource frameworks I used (Struts, Hibernate, Spring, you get the idea). As bad luck would have it, 9 times out of 10, I hadn’t the correct version when I needed it. That was both

Usually, there’s no such thing as a free lunch: in our case, this is a mistake. You can find here a fully comprehensive pocket guide for Ubuntu v8.04 & v8.10. Have a look and enjoy!