 I’ve been using Linux on servers in various flavours since 1997, but I am relatively new to Ubuntu and I have just started using Ubuntu as a desktop OS. Despite some installation problems, the overall experience was very positive. I had made earlier attempts to switch over to Linux, but for one or another reason these were thwarted, mostly because of the professional necessity of testing software under Windows. Since I am now working on cross-platform applications that particular constraint has evaporated. I spend most of my day developing software and writing documentation. Before installing Ubuntu, I was slightly concerned that there would be a temporary decrease in productivity due to having to learn new software. However, this turned out to be largely unfounded.
Most of the key applications like Eclipse, Firefox, Thunderbird, and OpenOffice work exactly the same under Linux as they do under Windows. The only major change was replacing Notepad++ (which only runs on Windows) by vi/vim. These editors are suitable for programming in situations where you don’t want to fire up an IDE. Furthermore, I have made some customisations to ease the transition, which I’d like to share with you. If you are new to Linux, you might find one or another useful for your own work. The following list is by no means exhaustive or even comprehensive, just a number of things I stumbled across during my first two weeks with desktop Ubuntu.
Repositories and download servers
Ubuntu maintains software packages with the Synaptic package manager. Because as a new user you are likely to make frequent use of this tool, one of the most useful things to do is to optimise its usage. This involves defining the repositories and the download server. Choose System/Administration/Software Sources from the main menu. In the first tab “Ubuntu Software”, select the four items marked with “main”, “universe”, “restricted” and “multiverse” for the widest choice of software packages. Next, optimise the download server. I wasted a whole day with downloading the 9.04->9.10 update, because of a slow server. Ubuntu can find the fastest server for you. Select “Other…” in the “Download from” dropdown-box. A dialogue with a list of servers shows on screen. Click on “Select Best Server” to let Ubuntu test all available servers for their response time and select the fastest one.
Keyboard and language customisations
If you are -like me- frequently typing text in different languages, chances are that the default language and keyboard settings will not suit you. Fortunately, Ubuntu is easy to configure for international use, possibly even superior to Windows in this regard. First, I added Thai language support in System/Administration/Language Support. Then I configured two additional keyboard layouts, German and Thai, in System/Preferences/Keyboard/Layout. As I am using a Thai/English keyboard, I have to remember the German key mapping by heart which is only of limited use. On Windows I got used to producing international characters by typing ALT+num key sequences. On Linux, this is even easier thanks to the concept of the compose key. In the keyboard layout dialogue, click on “Layout Options” which will show you a number of intricate keyboard customisation options. Click on “Compose key position” and pick a key, for instance “Right Alt”. Now you can use this key to compose international characters. For example, type right Alt, double quotation marks, and letter ‘u’ to produce the German Umlaut ‘ü’. Type right Alt, backtick and the letter ‘a’ to produce the accent grave ‘à’. Voilà!
Customising Nautilus
Nautilus is the Linux/Gnome equivalent to the Windows Explorer. In fact, I find it to be superior to the latter, because it supports protocols for remote access (such as ftp/sftp); it offers better search capability and better support for compressed files. If you prefer to work with a GUI rather than the command line, you would probably want to customise Nautilus in some way. The most obvious candidates for customisation are probably file associations. These can be defined by right-clicking on a file, selecting “Properties” from the context menu and switching to the “Open With” tab in the property dialogue. Here you can define alternative applications to use for opening a file, as well as the default application that is started upon double-click. If you need even more customisation options, install the package named “nautilus-actions”. This package lets you define custom actions for file entries in Nautilus which can be incorporated into the context menu. Predefined Nautilus extensions (aka shell extensions) for various file display and transformation purposes are also available.
Command line and terminal customisations
Ubuntu comes with the bash (Bourne again shell) and the Gnome-Terminal as command line defaults. These are fine for me. However, there is one feature which I found missing in the terminal application. It is not possible to search the output buffer. For example, when I run applications that produce a large amount of diagnostic output, there is no intuitive way to search trough this data, other than piping it into a command like “less”. I have found a little program named “screen” which appears to solve this problem. After “screen” is started, virtual sessions can be created within the same terminal window, each with its own searchable buffer. “Screen” involves remembering some arcane keyboard commands, but that’s the best I could find so far. Another command line annoyance is that the “vi” editor runs in compatible mode by default. This will let the cursors keys produce character output in insert mode; in other words, the cursor keys are broken. There is an easy fix for this, however. Put a file named .vimrc in your home directory that contains a single line saying “set nocompatible” and the cursor keys will work again.
Backup and antivirus software
Surprisingly, neither backup nor antivirus software packages are included in the default Ubuntu installation. Although viruses are probably not an immediate threat on a Linux system, I would rather not breed any of them on my machine. There is the open source software clamAV as well as a number of free-for-private-use commercial offerings for Linux. I am still evaluating antivirus software. So far I found clamAV and AVG quite usable, but not quite as convenient as under Windows. Backup software is an absolute necessity in my opinion, and I am surprised that it isn’t integrated in the original Ubuntu installation. Of course, individual backup needs differ, but a simple mirroring and archiving facility is probably required for even the most basic usage. Initially, I planned to hack a script based on rsync together for that purpose, but I have found something much nicer. The “backintime” package lets you create incremental backups with great ease and minimal storage requirements. Backintime revolves around the concept of snapshots; it is a GUI framework for rsync, diff, and cron. I highly recommend it.
 Today, I came across an interesting article in the Forbes Magazine entitled “Computing 2010″. The interesting part is that this article was written ten years ago. The author, Kip Crosby, imagined what computers would look like in 2010: optical circuits instead of silicon, with a CPU running at 100 GHz, holographic mass storage offering several TB capacity, 256 GB optoelectronic RAM, biometric authentication, voice control, completely wireless and shaped like a frisbee. Whew! Looks like Kip was just a tad too optimistic. Optoelectronics hasn’t caught on and most computers are still boxy rather than frisbee-ish. In fact, todays’s PC looks pretty much like that of 2000, except that its capacity has increased roughly following Moore’s law. The only accurate prediction is about mass storage capacity, although that didn’t require optical technology.
Personally, I’ve begun the new computing year with a major upgrade, though still far away from Kip’s 2010 vision. I have replaced my 32-bit Windows OS with a 64-bit Linux OS, doubled RAM from 4 GB to 8 GB and added another external USB hard drive for backups. The Ubuntu installation turned out a little difficult, because Linux did not want to cooperate with the BIOS RAID-1 configuration, so I had to switch to SATA mode and wipe out the Windows installation. The rest was easy, however. I used to worry about not being able to make my 3G USB modem work with Linux, but our maid has solved this problem for me. She obliterated the device by putting it into the washing machine. Can’t really blame her for that. I probably shouldn’t have carried the modem in the pockets of my shorts.
Back to the topic. What are the computing trends in 2010? Just off the top of my head: cloud computing is becoming a mainstream technology (or perhaps a mainstream buzz; time will tell). Along with that, virtualisation is now widely used. Supercomputers have broken the petaflop mark and now operate in the range of large clouds (> 1 PFlop). CRT monitors are quickly becoming relics of a past epoch. Single-core CPUs are headed the same way. Functional programming languages are beginning to catch on. 64-bit hardware and software are overtaking 32-bit systems in mainstream IT. Java 7 is announced for 2010. It surely looks like an interesting year.
 Once upon a time as a Java newbie, I thought that Java Server Pages were great. Back then I had done web development in Perl and PHP and I was pleasantly surprised by the similarity of the development process. It’s as simple as write and run. No bothersome compiler runs and deployment cycles. Java Server Pages seemed like PHP on steroids. Actually, I still think this is a fairly accurate description. It’s what the designers of JSP intended - Java’s answer to dynamic web scripting languages. The question is whether the JSP design is sound. After having spent several years in the Java Enterprise world, and having maintained large amounts of JSP code, I am convinced that it isn’t. So I am writing this article to tell you the untold nightmares of JSP programming.
Before we are going into that, let’s briefly look at the bright side. JSP technology is tempting for several reasons. First, it is mainstream and it bears the official stamp of approval by Sun. Second, it is an integral part of JEE and widely supported by application servers and tools. Third, it it is relatively easy to whip up dynamic content with JSP. So, why not use Java Server Pages? Well, there are several problems, the biggest of which are scriptlets. Scriptlets are embedded Java code. Because JSP allows you to mix Java code with markup, you get hybrid files which tend to become messy and difficult to maintain. Few HTML designers understand what’s going on in a JSP file. Few programmers are comfortable with mixing their code with reams of markup.
The typical production process for a JSP-based application looks like this: the UI designers finish their protoypes and hand over the resulting markup to the programmers. The programmers tear apart the HTML to make it easier to insert code, repeat sequences, and insert display logic. Once the programmers are finished, there is absolutely no chance that the designers will recognise the markup they produced. It is therefore also unlikely that they will ever touch it again. Even if the finished product contains no scriptlets, JSTL, expression language and (God help us) custom tags will confuse the hell out of designers. This means that the entire process has to be repeated, everytime a change of visuals is requested. This is however not the worst problem.
The biggest drawback is that there is absolutely no way to prevent application logic from creeping into the JSPs which ultimately leads to spaghetti code. You might think, “Oh well, I know how to code my JSPs properly.” At this point you should remember Murphy’s law, especially the part that says: “if something can go wrong it will go wrong.” Perhaps you are a disciplined individual who wouldn’t even dream about putting application logic into a JSP file. But can you say the same about the other programmers in your team? What if work needs to be completed under time pressure? Can you resist the temptation to solve a problem quick-and-dirty by putting a hack into a JSP file along with a “will fix this later” note? I have seen way too many “will fix this later” notes in JSPs and most of them were several years old.
My project consisted of an application with roughly 1.5 million LOC where about half of the code was implemented in JSPs. That’s about 1500-2000 JSP files. Most files were less than 500 lines, but some were in excess of 2000 lines. Once you hit upon an XL-sized JSP, it’s a safe bet that some crucial functionality is buried in it. Reading and understanding a 2000 line JSP can take several hours. Modifying and maintaining it is quite another deal. The project did not attempt to separate business logic from display logic in JSPs, thus XML was liberally mixed with scriptlets. While this approach works OK for narrow functionality that can be coded in a single JSP, it becomes very unwieldy for functionality that spans a larger problem space and, hence, many JSPs.
The “solution” for this was to use scriptlet fragments which are shared by multiple JSPs. This isn’t a real solution, however, because it forgoes almost all advantages of using an OOP language, such as abstraction, encapsulation, inheritance, and as a side effect it produces “ultra-tight coupling” between JSPs that use the same fragments. In theory, this can be made slightly less painful by defining inner classes in fragments for shared functionality. These class fragments are then included in the consuming JSPs at compile time. However, inner classes have their own limitations and compile time includes bulk up the resulting byte code. Since inner classes can access variables and methods in the outer scope, they lack proper encapsulation. Tying them to multiple consumers can lead to some weird dependencies and logical errors. Finally, there is no way to produce unit tests for scriptlets. The only way to test scriptlets is by inserting the test code directly into the JSP, which is obviously insane. In summary, there is no way to code scriptlets cleanly, so it’s best to avoid them.
But even without scriptlets, there’s plenty of trouble. For example, there is the Java standard tag library (JSTL) and the expression language (EL) which are supposed to replace scriptlets as coding instruments. In particular, the EL has been praised as enabling clean coding for MVC applications with Java Server Pages as view component. - Well, I disagree. - JSTL+EL are neither very clean nor very concise. What is worse, they are too powerful for their own good. JSTL+EL are Turing-complete, just like XSLT which they resemble, which means that replacing scriptlets with JSTL+EL is like jumping from the frying pan into the fire. In addition, JSTL provides tags that allow programmers to access a database and execute queries. If you see MVC going out of the window at this point, you have recognised the problem. In summary, JSTL+EL produce the same problems as scriptlets, but with an XML syntax.
In conclusion, Java Server Pages can lead to maintenance nightmares, especially when used in a large project. While it is possible to code JSPs cleanly, it is apparently not a widespread practice, which is probably Murphy’s law taking its toll. Hence, if you are building a new Java web application, think twice about using JSP. If you have a legacy application, you might want to replace JSPs by something more appropriate. In most cases, this can be done gradually whereas legacy JSPs can run side by side with an alternative view technology.
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