Javaland 2015

Javaland 2015

It is only a few days since a colleague of mine and i went to Javaland in Phantasialand near Brühl, so it is not to late to give you a summary of the talks i visited. Hope you enjoy :-)

Day 1

Day 1 started with "Lambdas and Streams, Functional Programming with JDK 8" by Simon Ritter. Even for those that were familiar with Lambdas and Streams Simon came up with some best practices using these new Technologies. He highly recommended to avoid using for-each and showed code examples how to do that while working with streams.

Next there was "Understanding Java Bytecode" with Rafael Winterhalter. He started with an introduction to Java Bytecode so everybody got an idea what that is and how you can use it to enhance your application. In the second part of his talk he introduced his ByteCode Framework "Byte Buddy". Byte Buddy has a fluent pattern based API to generate code during runtime. Check it out on http://bytebuddy.net

For all fans of NoSQL DBs Stefan Hochdörfer had a very interesting talk where he showed how to use PostgreSQL Features to mimic some NoSQL DB behavior. This can be done using one or more in combination of the following PostgreSQL Data types:

• Arrays
• hstore
• JSON / JSONB
• XML

With a ton full of examples he showed how to access fields of these types and how to manipulate them. It was very interesting to see how to access Array fields or JSON fields in one select Statement. You can find the PowerPoint at http://t.co/Qq9VsG7ugz

Even we visit JAVAland Javascript was subject of a lot of talks. So of "TypeScript, Javascript für Java-Entwickler" ("TypeScript, JavaScript for Java-Developers") by Kai Tödter. TypeScript is developed by Microsoft under an OpenSource Licence and brings known OO Features to Javascript. For more Information and Demos visit http://www.typescriptlang.org/.

After lunch we did a deep dive,  Daniel Mitterdorfer explained in "Make or Break: The Big Impact of Small Changes in Performance" how small changes in Java Code can influence or even break CPU Functionalities like CPU Caches and Branch Predictions. For Performance analysing he used JMH (http://openjdk.java.net/projects/code-tools/jmh/) that showed the differences after small changes. You can find his slides here: http://daniel.mitterdorfer.name/talks/2015/make-or-break/#/

Because Java Bytecode is fun i visited "Programming Java Bytecode with Jitescript" presented by Joe Kutner. Joe gave an introduction to Java Bytecode and ended with some Demos of Jitescript. Jitescript itself is only meant to create new classes during runtime, modifcation of existing Bytecode is not possible. If you are interested in Frameworks that manipulates or analyse Bytecode you should checkout Byteman, Javaassist or DRGarbage.