Saturday, August 30, 2014

Big Java News in Late Summer 2014

As is typical when JavaOne is imminent, there has been much big news in the Java community recently. This post briefly references three of these items (Java SE 8 updates, Java SE 9, and Java EE 8) and a "bonus" reference to a post I found to be one of the clearer ones I have seen on classpath/classloader issues.

String Deduplication in Oracle Java 8 JVM

In String Deduplication – A new feature in Java 8 Update 20, Fabian Lange introduces String Deduplication for the G1 Garbage Collector using the JVM option -XX:+UseStringDeduplication that was introduced with JDK 8 Update 20. The tools page for the Java launcher has been updated to mention the JVM options -XX:+UseStringDeduplication, -XX:+PrintStringDeduplicationStatistics, and -XX:StringDeduplicationAgeThreshold. More details on JDK 8 Update 20 are available in the blog post Release: Oracle Java Development Kit 8, Update 20. The Lange post has also sparked discussion on this and related JVM options on the Java subreddit.

Java 9 Features

Java 9 has been the hot topic of discussion in the Java community since the OpenJDK JDK 9 Project was announced. Long-awaited Java modularity (Project Jigsaw, which was booted from JDK 8) is probably the largest new feature anticipated for Java 9. Paul Krill writes in Why developers should get excited about Java 9 that "Jigsaw isn't the only new addition slated for Java 9. Support for the popular JSON (JavaScript Object Notation) data interchange format is key feature as well, along with process API, code cache, and locking improvements. The six JEPs currently proposed on that OpenJDK JDK 9 page are 102 (Process API Updates), 143 (Improve Contended Locking), 197 (Segmented Code Cache), 198 (Light-Weight JSON API), 199 (Smart Java Compilation, Phase 2), and 201 (Modular Source Code).

In the blog post Java 9 is coming with money api, otaviojava introduces JSR 354 ("JSR 354: Money and Currency API"), describes why it is needed, covers how it might be implemented, and concludes, "this API is expected to [be in] Java 9."

Java EE 8

Reza Rahman's post Java EE 8 Takes Off! talks about JSR 366 (Java EE 8 Specification) being kicked off. This post lists some of the anticipated high-level content for Java EE along with links to related JSRs.

Demystifying the Java Classpath

Java classpath issues are definitely one of the more difficult challenges that Java developers can face. The post Jar Hell made Easy - Demystifying the classpath with jHades provides a nice overview of some of the most common issues related to classpath and classloaders with concise and simple explanations of why these occur. I have not used jHades, but the quality of this post has definitely sparked my interest in that tool.


"Java" (SE, EE, JVM, etc.) keeps advancing and bringing us new language features, libraries, and tools. This post has referenced posts that highlight recent developments in JDK 8, JDK 9, and Java EE 8.

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