Reinhold advocates adding fiber to your Java diet in Oracle Code One keynote

Project Amber

According to Reinhold, Project Amber is all about rightsizing language ceremony. In this new era of machine learning and data driven microservices, it’s important for a developer to be able to express themselves clearly and concisely through their code. Project Amber attempts to address that, in a more meaningful way than simply templating boilerplate code.

In his keynote, Reinhold performed a batch of live coding, demonstrating the following three Project Amber features:

1. Local variable type inference
2. Raw string literals that don’t require escape sequencing, which is available as a preview feature in the JDK 12 early access release
3. Switch expressions with enums and type inferences which will enhance case based conditional logic

Project Loom

Working with threads in Java has always been a bit of a mess in Java. From their useless priority settings to the meaningless ThreadGroup, the age old API leaves plenty of room for improvement. “Threads have a lot of baggage,” said Reinhold. “They have a lot of things that don’t make sense in the modern world. In fact, they have a lot of things that didn’t make sense when they were introduced.”

Demoing a recent build of Project Loom, Reinhold demonstrated how easy it is to implement concurrent threads using Fibers, much to the delight of every software developer who has ever struggled with I/O blocking and concurrency issues. A full implementation of this new, lightweight thread construct appears to only be a release or two away.

Project Panama

Panama is the isthmus that connects North and South America, while also providing a canal that connects the Atlantic with the Pacific. Add to that, a project about connecting native code written in languages like C++ and Go with what’s running on the JVM. Panama is about improving the connection between native code, foreign data and Java.

“Many people know the pain of JNI, the Java Native Interface,” said Reinhold. Project Panama promises to make integrating with libraries written in other languages not only easier, but capable of significantly increased performance over the frustratingly throttled JNI bridge.

Project Valhalla

As everyone who codes Java knows, the language will not scale linearly. The JDK will scale, which is why languages like Scala and Kotlin are so popular. But the manner in which Java uses pointers and mutable data means throwing twice as many resources at an application under heavy load will not result in anything near a doubling of the throughput. But all of that is about to change.

“Today’s processors are vastly different than they were in 1995. The cost of a cache miss has increased by a factor 200 and in some cases 1000. Processors got faster but the speed of light didn’t.”
-Mark Reinhold, Chief Architect, Java Platform Group

Project Valhalla introduces value types, a mechanism to allow the data used by Java programs to be managed much more efficiently at runtime. Value types are pure data aggregates that have no identity. At runtime, their data trees can be flattened out into a bytecode pancake. When Project Valhalla is finally incorporated into the JDK, the whole performance landscape will change.

“Chasing pointers is costly,” said Reinhold. Objects have identity, they can be attached to a sync monitor and they have internal state. When your applications create a massive numbers of objects, as do big data systems or artificial neural networks, the impact on performance can be significant.

Like all good magic tricks, Project Valhalla’s is deceivingly simple. All it requires is a single keyword, value, to be added to the class declaration, and this small addition completely changes an instance’s data is managed. There are of course small caveats that go along with the value keyword’s use, but that’s to be expected. In a live coding demonstration, Reinhold added the value keyword to a class that performed matrix calculations, and the result was almost a threefold increase in executed instructions per cycle, along with notable changes with regards to how memory was allocated and how garbage collection routines behaved.

The future of Java holds in store a number of impressive improvements that will make programming easier and the applications we create faster. And the great thing about the new rapid release cadence is the fact that we won’t have to wait for all of these things to be finalized before we get to use them. When features are complete, they’ll trickle their way into the upcoming release cycle, with many of these features only being one or two release cycles away.