One of the hardest things to get right in Java is to figure out which class to use when working with time and dates. You have a recipe for disaster when you mix Java dates with timezone information with energy policy and a tight schedule. The U.S. Energy Policy Act of 2005 changed the start and end dates used for the Daylight Saving Time (DST). This policy had the potential negative effect of breaking millions of desktop computers, similar to the Y2K bug.

Software updates and patches where provided by software vendors such as Microsoft and Sun with plenty of time to spare before the new DST went into effect. The Microsoft patch was available as one of the thousands of security updates that you need to run on a Windows computer every so often. The Microsoft DST update was simply an exe installer. All you had to do to install the Microsoft DST update was to run it and restart your computer. Sun provided a Timezone Updater tool to patch Java with the new timezone data. The Java Timezone Updater is a jar file that you need to run from the command prompt with a series of command options. You need to run the Java Timezone Updater for each and every JRE available on the client machine! A typical client machine will have four to five different versions of the JRE.

Earlier this year when I was writing documentation and instructions for our field engineers for the new timezone change, I knew that the Java Timezone Updater was difficult for end users, even IT professionals, to run correctly. As mentioned you needed to run the updater manually from the command prompt, for every machine, for every JRE on a given machine, and there is no validation or test to notify you of success.

Well, just last week, three months after the DST change took effect one of our clients site started reporting a bug where they select April 2007 but our date widget rolls back to March 2007. After some time of head scratching, code reviews, and debugging we still were not able to reproduce the problem. After some time, it dawned on me that this might be a DST problem and sure enough we were to reproduce the bug on an updated JRE. For some reason, not yet completely explained but most likely related to human error, a whole set of computers where not patched correctly with the Java Timezone Updater. This DST bug locked out our users at this site from key UI screens at a critical time in their work flow.

We had people at the client’s site try to update our client machines with the Timezone Updater, but the bug still keep popping up. We then thought of fixing this in code with some sort of conditional chunk of code but that is just trying to fix a bad bug caused by a bad policy decision with a bad software hack because of a bad JRE update. Since our desktop client runs on Java Web Start, we thought that the best solution was to have our Web Start client run only on a newer version of the JRE that already has the correct and current timezone data. This is not entirely the most accommodating solution for the end user because each client machine now needs to have the correct JRE installed or else our application will not start.

In the end, we went with that hack, to have our JNLP restrict the version of the JRE used on our application. But this is not the best solution, since you have to update every client machines, just the scenario that Web Start promised you would not have to do! The takeaway message from this experience is that dates in Java are hard.

Technorati Tags: webstart, jnlp, jre, java, time, timezone, dst

iPhone Development

The iPhone Dev Camp started on Saturday by a nice presentation by Chritopher Allen, a MacHack veteran, regarding what is known about the iPhone from a web developer’s perspective. What is known is that the iPhone uses web standards (HTML, XHTML, CSS, JavaScript, PDF and Quicktime). Web 2.0 best practices apply for the iPhone, such as the proper use and sepration of HTML, CSS, and JavaScript. Christopher recommends avoiding the use of Flash, SVG, Java applets, embedded video, custom x.509 certificates, and framesets. Christopher also states the the finger is not a mouse and you need to design accordingly with large enough buttons and links with plenty of space between each other.
Fingers can do more than the traditional point and drag cursor such as double tap, touch and hold, one or two finger drag, flick, and pinch.

It might come as a surprise but many of JavaScript events don’t work, such as onscroll, onkeydown, onkeypress, onmousemove, etc. Some web development recommendations for the iPhone are to use columns and small blocks in the layout, such as floating divs. You should also use the tel: and mailto: protocols in links. You can also integrate with Google Maps simply by adding your location search to maps.google.com/maps? URL.

The current activity on the the iPhoneWebDev Google Groups seems to be focused around iPhone specific development libraries, implementing the infamous back button, debugging JS, optimizing application for low bandwidth, and hacking the viewport. There is also a series of open questions such as, what level of support is there for the canvas tag? What level of persistent storage is available, cookies? The right questions will lead to the right answers. I have also published a great list of available iPhone development resources.

Most of time at the iPhone Dev Camp was spent developing a collaborating for the hack-a-thon. This was a working camp focused on developing some really cool applications on the iPhone.
Read more »

Here is a list of links to the best available iPhone development resources such as simulators, development plugins, wikis, and other JavaScript/HTML/Safari documentation.

• iPhoney - A free iPhone web simulator for designers.
• iPhone Interface in JavaScript - A JavaScript based iPhone simulator.
• iPhone Simulator - Yet another JavaScript-based iPhone simulator.
• Morfik Builds First iPhone Development Tool - Development tool for iPhone.
• Aptana IDE: iPhone Development Plugin - Aptana iPhone development plugin for Eclipse.
• Firebug for iPhone - “Trying to debug web pages on my iPhone transported me back to a dark place I hadn’t been in some time: The Land of alert() Debugging!”
• iPhone Dev Wiki - iPhone development wiki.
• Apple iPhone development secrets revealed - Some development tips and advice.
• iPhone Javascript and spec benchmark - Some iPhone benchmarks.
• iPhone Web Development Tips - Tips available from Ajaxian.
• iPhone Dev Camp - iPhone devcamp in San Francisco.
• iPhone Web Dev - iPhone development Google group.
• Web Develpoment for iPhone - Official Apple Developer Connection documentation.
• JavaScript Coding Guidelines for Mac OS X - JavaScript basics and best practices.
• Introduction to the Document Object Model - DOM basics.

Bonus Resource

• IPhoneWebDev - Some nice web examples and tips for the iPhone.

Technorati Tags: iphone, development, webdev, apple, safari, javascript, iphonewebdev, iphonedev, iphonedevcamp

I have a really good friend that runs a small travel related blog and she wanted to add Google Maps to her site to go along with her articles, such as this post on LA restaurants. But she is a not a developer and would never ever want to tinker with the necessary JavaScript code used by the Google Maps API. To help in her task of generating custom maps I quickly whipped up Map Builder. Map Builder allows you to zoom in, center, and add any number of markers to a Google Maps canvas. Once you are happy with how a map looks, you can generate the necessary JavaScript code which can be embedded in you website. You do need to sign up for a Google Maps API key before you can display the map on your domain.

On the technical side, I use the Google Geocoder to resolve the longitude and latitude of a given address. Creating a marker for that location is pretty straight forward and there are plenty of examples in the Google Maps documentation. To generate the custom JavaScript source code I used the JavaScript Templates library from the Trimpath project.

Technorati Tags: javascript, js, trimpath, javascript templates, google maps, map builder