Simon is a Developer Advocate at ZeroTurnaround, a Java Champion since 2014, JavaOne Rockstar speaker in 2014, Virtual JUG founder and organiser, London Java Community co-leader and RebelLabs author. He is an experienced speaker, having presented at JavaOne, JavaZone, Jfokus, DevoxxUK, DevoxxFR, JavaZone, JMaghreb and many more including many JUG tours. His passion is around user groups and communities. When not traveling, Simon enjoys spending quality time with his family, cooking and eating great food.
There are more than 50 actively worked JVM languages in existence today. Some have been ported to the JVM, whereas others were written specifically for the JVM. This hands-on session takes an introductory (but non-Hello, World) look at several JVM languages, including Java 8, Scala, Groovy, Kotlin, Ceylon and Xtend. It covers ZeroTurnaround’s initial experiences, including what rocked and sucked in learning each one. You don’t need any prior knowledge of these languages to attend the session. You will learn whether they are for you and will hear about some real-life experiences of trying these languages for the first time.
Class loaders are at the core of the Java language. Java EE containers, OSGi, NetBeans modules, Tapestry 5, Grails and many others use class loaders heavily. Yet when something goes wrong, would you know how to solve it?
In this session we’ll take a tour of the Java class loading mechanism, both from JVM and developer point of view. We’ll see how different delegation systems are built, how synchronization works, what is the difference between finding classes and resources, what wrong assumptions has been made and are now supported.
Next we will look at typical problems that you get with class loading and how to solve them. ClassNoDefError, IncompatibleClassChangeError, LinkageError and many others are symptoms of specific things going wrong that you can usually find and fix. For each problem we’ll go through a hands on demo with a corresponding solution.
We’ll also take a look at how and why classloaders leak and how can you remedy that.
