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Java Mind Gymnastics

Posted by kabutz on February 16, 2012 at 2:46 PM PST

I like a good Java puzzle.  The trickier the better.  In this article I will tell you about a new set of puzzles by Wouter Coekaerts that will melt your Java brain.

About five years ago, I was suckered into participating in a Java Black Belt competition at a Java Tech Days in London.  This was in the days before Her Royal Highness decided she had had enough South African visitors and thus closed the door for me by asking us to get visas.  Since I live on an island in the Mediterranean, acquiring a visa means flying to Athens and handing over my passport to the British Embassy for 6 weeks.  I travel at least once a month, so it will be a while before I can enjoy the warmth of English beer again.  The Java Black Belt competition consists of a bunch of questions, ranging from hard to very hard.  You have a limited time to answer them.  If you are lucky, you get given a set of relatively easy questions.  During the competition, I was lucky to get a high enough score, so that I got to the top of the scoreboard.  It was not a brilliant score by any means.  Olivier Croisier, my French instructor, scored a perfect 100% in the Sun Java Programmers Certification.  My score was probably about 95%.  Fortunately, someone recognized my name and told his buddies that they had no chance of dethroning me.  As a result, no one tried after me and I won a book called the Java Puzzlers.  I reviewed it on The Java Specialists' Newsletter.

Olivier Croisier publishes some excellent Java puzzles in his blog called "The Coder's Breakfast".  It is in French, but don't let that put you off.  Olivier does a very nice job of translating it to English for those of us who do not understand a word of French.  The name conjures up images of sitting in a Parisian cafe with a newspaper, watching the world go by whilst the butter is melting in the warm croissant and your cup of hot coffee is filling the room with a pleasant aroma.

And lastly, we have a hot new contender on the puzzle scene, Wouter Coekaerts.  He sent me some of his puzzles about a year ago and I've been begging him since then to please release them to the world.  They are funny and very challenging.  Definitely something for an advanced Java programmer.  You can use some dirty tricks, but nothing that would break the security manager.  Here is his first puzzle.  After a couple of weeks, Wouter will show the solution and his next puzzle.

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