Using threads and AtomicInteger
From Groovy you can use all of the normal concurrency facilities in Java and combine them with threads and closures as necessary. E.g. a (slightly modified) atomic counter from a Groovy example here:
A Groovy script to naively calculate the Fibonacci series inspired by the example here. Note: a version using memoizing will be much more efficient but this illustrates using Java's built-in concurrency primitives from Groovy.
If you want to convince yourself that some threads are actually being created, replace the last each line with:
Fibonacci with Functional Java
If you wish to make use of the functionaljava (tested with 2.1.3) library , you could use a Groovy program such as this:
An example using Exchanger. We have two threads - one keeping evens and exchanging odd values with the other thread. Meanwhile the other thread is working in reverse fashion; keeping the odds and exchanging the evens. The algorithm here is dumb in that it relies on the same number of swaps for each side - which is fine for this example but would need to be altered for more general input values.
Catching Exceptions with an Exception Handler
When catching Exceptions with an exception handler in Groovy Scripts, there is potential for interaction with Groovy's runtime which catches exceptions and filters stacktraces. The best way to avoid this interaction is to create your own thread and call setDefaultUncaughtExceptionHandler directly on that thread instance as per below:
* Functional Programming with Groovy
* Multithreading with SwingBuilder