Devoxx4Kids Denver: Having fun with littleBits

A little more than a week ago, on a beautiful Saturday morning, a number of Denver kids converged at Assembly to learn about hardware concepts with littleBits. This meetup was a bit different than our last meeting in that the kids built stuff with their hands rather than on computers.

Supplies Devoxx4Kids Sign

The workshop was taught by Juan Sanchez of Tack Mobile. Juan did an excellent job of keeping his presentation short and sweet and got the kids building things within the first hour. The event space provided by Assembly was excellent and we look forward to December's Greenfoot Workshop at the same location.

Juan in Action

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Posted in Java at Dec 02 2014, 12:10:49 PM MST 2 Comments

Devoxx4Kids - Denver: Introduction to Hardware Concepts with littleBits

Devoxx4Kids I'm pleased to announce the second meeting of the Denver Chapter of Devoxx4Kids is now open for registration. It's a two hour class titled Introduction to Hardware Concepts with littleBits and will be taught by Denver's own Tack Mobile. To learn more about littleBits, see http://littlebits.cc. If you or your company would like help by donating a Workshop Set, please contact me.

The class will be held on Saturday, November 22nd, from 10am - 12pm at Assembly Workspace. Cost is $10, but you'll get that back in the form of a t-shirt. Age requirement is 9-18 and kids should have basic computer skills (copy/paste, opening applications, etc.).

I'd like to thank Juan Sanchez for reaching out to me about this class and inspiring his company (and workspace) to make it all happen. It's been great working with you and your team Juan!

When I started Devoxx4Kids Denver, I was hoping to host a class or two per year. Our first meetup in May was a wild success. After taking the summer off to relax, I started looking for more speakers in early October. The response has been great and we'll have another class about GreenFoot on December 13th. We're even in the planning stages for another session on NAO Humanoid Robot programming in Q1 2015.

If you'd like to get involved with Denver's Devoxx4Kids, please join our meetup group.

Posted in General at Oct 30 2014, 08:17:21 AM MDT 1 Comment

First Devoxx4Kids in Denver a Wild Success!

The first Devoxx4Kids Denver was a wild success! This last Saturday, 20 enthusiastic Minecraft hackers gathered at Thrive in Cherry Creek to learn from one of the best. With masterful skill, Scott Davis, founder of ThirstyHead.com, taught everyone how to get a development environment setup, run a local Minecraft server and install plugins into it. You can see the materials we used for this class on Scott's site, at Introduction to Server-side Minecraft Programming.

McGinity Photo was kind enough to snap a bunch of pictures, which you can find on Flickr. A sampling is below:

Devoxx4Kids Denver Devoxx4Kids Denver Devoxx4Kids Denver

Scott Davis Thanks for the great room Thrive!

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Posted in Java at May 05 2014, 11:42:30 PM MDT Add a Comment

The Modern Java Web Developer and Java Web Security at Denver JUG

Last night, I had the pleasure of delivering two talks at the Denver Java User Group. The first talk, The Modern Java Web Developer, was inspired by the book titled The Well-Grounded Java Developer. Ben Evans and Martijn Verburg mention in the beginning of the book that they wrote it as a training guide to get new Java developers up to speed. For my talk, I wanted to do something similar, but for Java Web Developers.

I mentioned that the first thing you have to do to become modern is to change your title from a Java Web Developer to a JVM Web Developer. After doing that, you have a whole slew of new and wonderful technologies at your disposal. From there, I believe the Modern JVM Web Developer:

  • Starts with Fast Hardware
  • Uses IntelliJ IDEA
  • Leverages jQuery, HTML5, and CSS3
  • Creates High Performance Web Sites
  • For Mobile Devices
  • In the Cloud
  • And cares about Security

You can also view this presentation on Slideshare or download it from my presentations page.

The second talk was on Java Web Application Security and was largely an updated version of the talk I gave a couple years ago, starting with an appearance at the Utah JUG. It was mostly a live demo session using my Ajax Login application. To prepare the project for this talk, I created branches for each step. This means you can checkout the "baseline" branch and use Git to compare it with the "javaee" branch. You can also compare the "spring-security" branch vs. the "apache-shiro" branch. Finally, you could see what I needed to do to fix many of the vulnerabilities found by Zed Attack Proxy.

You can also view this presentation on Slideshare or download it from my presentations page.

Thanks to the DJUG and Thrive folks for providing good beer (especially the Guinness!) and FullContact for hosting. Also, I'd like to thank Manning for the copies of The Well-Grounded Java Developer they sent and No Starch Press for copies of Michal Zalewsky's The Tangled Web: A Guide to Securing Modern Web Applications. Last, but certainly not least, thanks to all the good people who attended and listened to me ramble on about all this cool technology.

Future speaking engagements include Devoxx France in March and Denver's HTML5 User Group in April.

Posted in Java at Feb 14 2013, 10:23:18 AM MST 2 Comments

Denver Yard Harvest Kick Off Party

When I first moved into my house, I was pumped to have fruit trees in my backyard. However, I quickly realized the downside:

I have the biggest apple tree I've ever seen and it drops apples like they're going out of style. I counted them in a 24-hour period last weekend and there was 100 new apples! I thought it was cool when I first moved in, but now it seems like a lot of work. However, it's such a good shade tree, it'd be a shame to do anything to it.

I've since grown to love my apple tree, plumb tree and grapes. They produce a lot of fruit, but I rarely pick and eat it.

Nice Deck, but lots of apples (daily) Plum Tree and Grapes too

Because I have so much fruit, I was pumped when my good friend Jason Barton moved back to Denver and started Yard Harvest. Their homepage explains their mission:

What We Do: Each fall, homeowners who register their trees with us call when those trees are dropping apples, cherries, peaches, and other food in their yards. Our volunteers harvest the fruit, leave as much as the homeowners would like, and deliver the rest to daycare centers, homes for the elderly, community kitchens, and other places that serve people around Denver who are at risk of going without fresh, healthy food.

Jason started a similar initiative in Vancouver, BC a few years ago and had great success. I'm writing this post to create awareness of Yard Harvest in Denver and invite you to the Kick Off Party. Below is a picture of the flyer that's being passed around and you can download the PDF if you want to print it out and help spread the word.

Denver Yard Harvest Kick Off Event

Hope to see you there!

Posted in General at May 25 2011, 09:37:53 AM MDT Add a Comment

Two Opening Days with a Stopover in Kraków

Opening Day is a special event in Denver. The night before, it feels like the whole city is alive in anticipation of the big event. On Opening Day, it's typically a gorgeous spring day and serves as a great kickoff to baseball season. This year, we decided to take things up a notch and hit two opening days instead of one. The dates just happened to line up so we could go to the Rockies Home Opener on April 1st, fly to Kraków for the 33rd Degree Conference and make it back to Boston for the Red Sox Home Opener. Since Trish's brother lives near Boston, and I have good friends there, it sounded like the perfect vacation. To make a crazy vacation schedule even crazier, Trish and I moved in together the day before it all started. With moving and trying to finish my basement sauna before we left, we've definitely had a hectic few weeks.

Nightmare with water? Yeah, Trish'll do that to ya! Sarah and Joe Rockies Opener! Cargo!

After attending the Rockies Home Opener and having a great time with friends, we got to bed early and woke up on Saturday for our flight to Kraków. It was a 2 o'clock flight, so we got lots of sleep and then proceeded to thoroughly enjoy our flight when we upgraded to Business Class from Chicago to Munich. Business Class is the way to travel internationally. We arrived just after noon on Sunday and spent the afternoon exploring Kraków's Old Town and trying to stay awake. The weather was beautiful and it seemed like it might've been the warmest day of the year.

St. Mary's Basilica, Kraków Main Market Square St. Mary's Flowers

On Monday, we spent more time in the center of Kraków, wandering through the Main Market Square, Wawel Castle and the very cool Dragon's Den. We had lunch outside, again enjoying the great weather and some local beers. We were surprised to find that kamikaze shots are served in groups of four, rather than just one like it's done in the US. That evening, we enjoyed an excellent Italian dinner at Aqua e Wino.

The Grunwald Monument Church of St. Adalbert Renaissance courtyard of Wawel Castle Wawel Hill

On Tuesday, we headed to Aushwitz. This was a very sobering experience, but I'm glad we did it. It made me wonder if this type of thing could happen again, only to realize that it has. That evening, we sipped on martinis at the Metropolitan.

Auschwitz concentration camp Rudolf Höss was hanged here on 16 April 1947. Auschwitz Martinis at Metropolitan

On Wednesday, I delivered my talk on Comparing JVM Web Frameworks. You can download the PDF or view the presentation on Slideshare if you're interested. The conference itself had a spectacular schedule and speaker lineup, so I was a little disappointed I didn't attend any sessions. We did make it to the ZeroTurnaround Party that night and had a lot of fun talking to Grzegorz, Martijn and Anton.

We woke up Thursday and headed to the airport for our flight back to the US. We landed in Boston at 6:30 pm and headed to my friend Chris's house in Concord. You might remember Chris from my first game at Fenway Park. Friday, we joined other friends, hopped on the train and headed to Yawkey Way for a beer before the game. Our seats were in the bleachers, but we had a fantastic time watching the Red Sox win their first game of the year.

Fenway Paak! Morse and Kidder Happy Siblings Erika and Julie Red Sox Win!

We went to another game on Saturday with Trish's brother and a friend of his. We then proceeded to spend a relaxing Lazy Sunday with his family before flying back Monday morning.

Thanks to all our friends who participated in the opening day festivities as well as to Grzegorz Duda for inviting me to speak at 33rd Degree. We had a blast!

If you'd like to see more pictures from this adventure, please see Two Opening Days with a Stopover in Kraków on Flickr.

Posted in Java at Apr 14 2011, 09:40:47 AM MDT Add a Comment

WebSockets with Johnny Wey at Denver JUG

This evening, I attended Denver JUG to hear Johnny Wey talk about WebSockets. This month, the location moved and even though I had a nice bike ride to the meeting, I showed up about 20 minutes late. Johnny's talk lasted about 40 minutes, so I missed the first half.

When I arrived, he was talking about workarounds for implementing push applications in browsers. He had a slide that talked about Comet and iframes as the common implementation, and the other major option being ActionScript's XMLSocket. The biggest issues with XMLSocket (according to Johnny) are:

  • Not available on many modern mobile platforms.
  • Flash and managing / detecting plugin versions can add unwanted complexity.
  • Many would consider Flash solutions deprecated.

The biggest issue with implementing push on a client is managing it all, especially if you need to support older browsers. Socket.IO is one possible solution. It rides on the coattails of node.js. Features of Socket.IO include:

  • Abstracts socket methods into a unified API.
  • Open source (MIT) with active community.
  • Multiple server implementations (including Java) with the "reference" implementation developed in node.js.

The client API looks as follows:

var socket = new io.Socket(); 
socket.on('connect', function(){ 
  socket.send('hi!'); 
}) 
socket.on('message', function(data){ 
  alert(data);
})
socket.on('disconnect', function(){}) 

jWebSocket is another solution and it's where a lot of the Java WebSocket development is ending up right now. Highlights about the project include:

  • Open source (LGPL) with relatively active community.
  • Servlet-like API.
  • More "enterprisey" than Socket.IO.

Other options include CometD, which is a Dojo-driven Comet implementation that uses a specification called Bayeux. Jetty and GlassFish both support WebSockets in various forms of functionality and stability. Finally, there's Pusher (a SaaS implementation of push with a RESTful API) and Atmosphere (a container-agnostic framework).

How do you scale web sockets? The same way you make a webapp scale:

  • Go stateless
  • Use short request / response cycle
  • Use the smallest payload possible
  • Cache as much as possible

Scaling challenges with web sockets:

  • Connections have intrinsic state (they never close!)
  • Communications pipeline to your app server
  • Some sort of introspection on LB side (JMX)

There's also some existing controversy in the WebSockets Community, mostly around using Upgrade vs. CONNECT with HTTP. An (IETF) experiment found Upgrade portion of HTTP protocol was often improperly implemented by proxy servers and other network hardware. This seems to have caused Google Chrome to deprecate using Upgrade in favor of CONNECT. CONNECT used in this manner is seen by many as an abuse of the web.

Other useful links that Johnny provided were What can I use… to find out native support across browsers. For example, you can see which browsers support websockets. He also pointed out that websocket.org provides a good intro to WebSockets.

I'm glad I attended Johnny's talk. I've been a little leery of using WebSockets in my applications because of older browsers. Now that I'm aware of frameworks (like Socket.IO) that solve this problem, I'm eager to try it when the need arises.

Related: Dojo/Comet support in Java Web Frameworks

Posted in Java at Mar 09 2011, 07:10:12 PM MST Add a Comment

An Epic Weekend in Estes Park

A couple years ago, a good friend and I headed up to Estes Park for a day at the Longs Peak Scottish-Irish Festival. I was so impressed with the venue, views and music that I vowed to return. Last weekend, I invited my super-fun friend Trish for a party in the hills. I'm happy to report it was once again an awesome festival, with perfect weather.

Back to the Future Beautiful View Plane in Sky Nice Backdrop

Happy Refreshing Ride to Stanley Hotel View from The Stanley Hotel

Highlights of the weekend included: dining at The Rock Inn, the parade, riding bikes around town, lunch at The Stanley Hotel, fly fishing along the river, Ed's Cantina and many hours of excellent Celtic music. For more pictures, checkout the full set on Flickr.

After leaving Estes Park on Sunday, we drove back to Denver, hoping to watch the Broncos game in LoDo. At one point, I thought I'd have to listen to the whole game on the radio. Luckily, we got hooked up and got to watch the 4th quarter. My sadness over the Broncos loss was erased within a couple hours as we celebrated Jason Giambi's walk-off home run at the Rockies game. You gotta love that it's already been documented on WikiPedia.

In other news, Jack's turned 6 a couple weeks ago. He's in 1st grade now and currently into Super Mario on Wii, Bakugans, and Transformers. He also seems to have an intense addiction to Angry Birds on my iPhone. We had a blast celebrating his birthday at Chuck-E-Cheese and the Broncos game.

Watch out!

As summer fades and fall starts to kick in, I'll be attending the Great American Beer Festival, the Denver Broncos home opener with my sister, training for ski season and (hopefully) enjoying Rocktober. I love fall in Denver.

Posted in General at Sep 15 2010, 12:13:38 AM MDT Add a Comment

What's New in Maven 3.0 with Matthew McCullough

Last night, I attended the Denver JUG meeting to hear some excellent talks by Matthew McCullough and Tim Berglund. I took notes during Matthew's talk, but my battery ran out before Tim's talk started. Below are my notes.

Matthew started out by described the differences between Maven 2 and Maven 3. As he began, he emphasized it wasn't a beginner talk, but mostly for existing Maven users that understand how to read a pom.xml and such.

The Roadmap
Commits to Maven 3 have been happening for the last 3 years. Matthew is not an employee of Sonatype, but he mentioned their name quite a bit in his talk. Sonatype has hired several committers (7 that Matthew knows of by name) that now work on Maven 3 full-time. For compatibility with Maven 2, the project has 450 integration tests and they test it against 100s of Maven 2 projects. Maven 3 has plugin classloader partitioning and a legacy simulation layer for old plugins.

The main improvement in Maven 3 is speed. It's been performance tuned to be 50% to 400% faster. Benchmarks (guaranteed by integration tests) include better: Disk I/O, Network I/O, CPU and Memory. Another new feature is extensibility so Maven is a better library rather than just a command-line tool. Now there's a library and APIs that you can use to do the things that Maven does. Plexus has been replaced with Guice and it's now much easier to embed Maven (Polyglot Maven and Maven Shell are examples of this).

Below are a number of other changes between Maven 2 and Maven 3.

  • Syntax: pom.xml still uses <modelVersion>4.0.0</modelVersion> so it can be a drop-in replacement for Maven 2 projects.
  • Validations: poms are heavily validated against common mistakes, warns when plugin versions are not specified (use mvn validate to see issues), blocks duplicate dependencies (examined in same POM only, conflict resolution used otherwise).
  • Help URLs: wiki page URLs now shown for all error messages. One of the first Apache projects to do this.
  • Removals: profiles.xml external file support removed, Maven 1.0 repository support removed <layout>legacy</layout> (it's been 5 years since any commits to Maven 1).
  • Behavior: SNAPSHOTs always deployed with date-stamps, artifact resolution caching has been improved to do less checking (override with mvn <phase> -U).
  • Plugins: version auto-selection favors RELEASEs over SNAPSHOTs (opposite for Maven 2), versions cannot be specified as RELEASE or LATEST, plugins only resolved from <pluginRepository> locations.
  • See the Plugin Compatibility Matrix to see if your favorite plugins are compatible.

Maven 3 hopes to be a drop-in replacement for Maven 2, but non backwards-compatible changes will be happening in Maven 3.1. It's anticipated release is Q1 of 2011 and will likely contain the following features.

  • "Mixins" for direct dependencies
  • Site plugin takes over <reporting>
  • Backwards compatibility by <modelVersion
  • There's a good chance 3.1 breaks compatibility with legacy POMs

Another new thing in Maven 3 is Toolchain. Toolchain a common way to configure your JDK for multiple plugins. There are only a handful of plugins that are toolchain-enabled. User tool chain definitions are defined in ~/.m2/toolchains.xml. To use different toolchains (JDKs), you specify a vendor and version as part of your plugin configuration.

Maven Shell is a high performance console that's a Maven 3 add-on. It's hosted at GitHub to make community contributions easier. It goes on your command line and it offers syntax highlighting and context-sensitive help (by typing ? at the command prompt).

Another major improvement in Maven 3 is Polyglot Maven. Tools like Gant and Buildr have made Maven look ancient, but they've also given it a good challenge. Maven 3 is likely to leapfrog these tools because of its ability to use different languages for your build configuration. Currently, 6 languages are supported. Polyglot Maven is a super-set distribution of Maven 3. It's not shipped with Maven 3 core because it contains all the other language implementations and is quite large. Polyglot Maven also contains a translate tool that allows you to convert any-to-any language. It has a DSL framework with Macros and Lifecycle Hooks. Macros allows for more concise syntax.

After talking about Polyglot Maven a bit, Matthew shows us a demo translating pom.xml to pom.yaml and then running the build. After that, he showed us examples of what a pom looks like when defined in Clojure, Scala and Groovy. Someone asked about file parsing performance and Matthew said different languages would cause a single-digit performance difference as part of your build process. Personally, I can't help but think any non-XML parser would be faster than the XML parser.

In regards to m2eclipse, a new drop (0.10) occurred a few weeks ago and it's one of the highest quality releases to date. It has major refactoring and many performance improvements.

For sample Maven projects see Matthew's Maven Samples.

I very much enjoyed Matthew's talk, both because of his presentation techniques and because he had a lot of good information. While I've tried Maven 3 and Shell in the past, I've been newly inspired to start using them again on a daily basis.

Tim's talk on Decision Making was also excellent. The biggest things I learned were that conflict is good (idea-wise, not personal) and things to look out for between teams (fault lines). Hopefully both Tim and Matthew post their slides so I can link to them here.

Posted in Java at May 13 2010, 03:54:21 PM MDT 1 Comment

My Guest Room Remodel is finished!

On December 5th, I flew home from Orlando (after The Rich Web Experience) and arrived home to the sound of waterfalls in my house. As soon as I opened the door, I knew something was wrong. Sure enough, the pipes had burst in my back guest room and water was pouring out of my ceiling. My guess is that it'd been happening for days.

Waterfalls - a.k.a. Pipes Burst What we came home to: busted water pipes. Soaked through the walls Time for a remodel!

The following week was quite interesting as I juggled a cleanup with lots of fans and a house without water. My water got turned on by Wednesday and I gained a whole new appreciation for indoor plumbing. Initially, I thought I could get everything fixed before my family arrived for Christmas. As their arrival approached, I became less and less hopeful and quickly scrambled to setup a couple ad hoc guest rooms.

After the Christmas holiday, I met with a local contractor (the same guy who fixed my plumbing initially) and discussed my options. The cheapest option (a.k.a. the one my homeowner's insurance would cover) was to put everything back like it was. However, it was readily apparent that if we did this, there's a good chance busted pipes would happen again. Therefore, I made the leap and decided to remodel the whole thing. Major changes made were 1) moving the bathroom to an opposite corner, 2) adding an interior window for light from the skylights and 3) adding a door to the bathroom from Jack's room.

Tearing out walls Old bathroom gone Soon to be better

Digging, lots of it. Cement gone. Framing

The results are something I'm very happy with. I'd like to thank Nu Image for their great work and my parents for flying in to help finish it all up. If you're a friend of mine and looking for some powder runs this winter, I have a nice guest room for you to stay in. ;-)

Remodeled Guest Room Bathroom Sink
Wall Mirror Closet View into Shower View from Jack's Room

For more pictures, see my Guest Room Remodeling set on Flickr.

Posted in General at Feb 16 2010, 07:49:37 AM MST 2 Comments