Java 12- What To Expect And How To Prepare

How Java 12 Cleverly Upsells With New Changes And Features

Diving over the most critical areas of Java programming – The Java language, libraries, JVM and other relevant JDK features, Java 12 have come up with new and prominent features that users will crave acceptance for in these key sections.

With the release of Java 12 on March 2019, it is advised that all users deploy their applications on the newest version of Java. This will help all the tech-breathing community, especially the users in Java language, keep their programming know-how up-to-the-minute and also broaden their views on the entire performance improvements and changes that have come through with the Java 12 release!

Some of the greatest benefits you can expect from the new Java 12 and how you can prepare yourself for accelerated performance are:

  • Easier coding process. For instance, the new ‘switch’ statement/ expression.
  • Introduction to JVM constants API modeling for the key class-file and run-time entities, to manipulate classes and methods.
  • Introduction of a new collector named ‘teeing’ which uses the teeing method to evaluate the average of input parameters.
  • Garbage collection has been made easier with reduced pause times and segmentation, regardless of the heap size, than ever before with JDK 12.
  • The new AArch 64-bit port, eliminating the need for two to improve efficiency and getting rid of redundant work.
  • Promotes a streamlined execution of existing benchmarks and addition of new into a whole new suite from JDK 12.

Related Reading: Find a complete list of JAVA Trends rolling out this year.

To start with, there are differences, enhancements, certain APIs and features removed, and certain others deprecated. Let’s prepare for a deep dive into Java 12 features and changes:

The Unicode 11.0.0 Support

The previous version of JDK 11 supported Unicode 10.0.0. With the release of JDK 12, the most important changes include:

  1. Addition of 684 new characters (66 emojis, copyleft symbol, half stars for rating systems, Chinese chess symbols, astrological symbols etc)
  2. 7 new scripts (namely the Hanifi Rohingya, Sogdian, Dogra, Makasar, Medefaidrin etc.)
  3. 11 new blocks (7 for new scripts and 4 for the existing scripts like Mayan numerals and Chess symbols).

JVM Constants API

The new package java.lang.invoke.constant introduced with Java 12 brings about this new API and is used to model nominal descriptions of the class file and run-time entities, especially the constants that are loaded from the constant pool. This API will contain classes such as ConstantDesc, ClassDesc etc.) that include the information to describe the constants from the constant pool.

Compact Number Formatting Support

This feature provides support for formatting numbers in their compact form. These formats are defined by LDML’s Compact Number Formats. For instance, in the en_US locale, 1000 can be formatted as “1K”. For this, factory methods by NumberFormat are used to obtain instances as described in the above example.

The Z Garbage Collector

The ZGC has started to support class unloading feature with the advent of Java 12. Now, data structures related to the unloaded classes can be freed. This takes place without impacting the garbage collector’s pause times and also does not interfere with the execution of the application threads. This feature is enabled by default.

The Beta Switch Expressions

Pattern matching techniques were used in widespread to resolve issues that existed with the switch statement. This included the default single scope switch block, the flow behavior of switch blocks and also when the switch statement worked as a single statement. The switch statement used the fall-through semantics, which is error-prone.

With Java 12, the switch statement uses the ‘lambda’ expression to return from the switch statement. This removes the need for the usual break statements. Also, the switch is treated as an expression. That is, it can either have a value or return a value.

Related Reading: Check out some cool tips to make Android App development easy.

Promptly Return Unused Committed Memory From G1

JDK 11 was compatible with G1 being able to return some of the committed memory back to the Operating System for other applications to run. But it could do this only during concurrent cycles. With Java 12, G1 is able to retain committed memory for a longer time period, that is, during a full collection.

This happens because during low memory usage which leads to inactivity of the applications, G1 either tries continuing or it triggers a concurrent cycle to evaluate the overall Java heap usage. With this, the unused memory is now returned to the OS on time.  This feature promises a more stable memory utilization for the JVM.

Shenandoah: The low-pause-time GC Algorithm

Shenandoah is a garbage collector that aims at reducing pause times because here, pause times are independent of the heap’s size. This feature was implemented and supported by RedHat for aarch64 and amd64.

The Shenandoah algorithm guarantees low response times, that is, the lower end being 10-500 ms.

Default CDS Archives

The class data-sharing (CDS) archive is built with the aim of improving the JDK build process. It is performed with the default class list on the 64-bit platform. It has a better start-up-time, prevents the need to run the default -Xshare  :dump class list.

For CDS to be used, an archive that loads the classes when an application starts, is a requisite. With JDK 12, the classes.jsa file in the lib/server directory is now available.

Microbenchmark suite (JEP 230)

The Java Microbenchmarking Harness (JMH) was developed to deliver a rich framework for developing performance benchmarks for Java applications. It simplifies the execution of existing benchmarks and also supports the creation of new ones. It is based on the Java Microbenchmark Harness (JMH) and allows easy testing of JDK performance.

It includes around 100 benchmarks as a start functionality.

One Aarch 64 Port (JEP 340)

Java 12 will now support only one port for the ARM 64-bit processors. This is to get rid of redundant work needed for 2 ports as the JDK 11 had two ports for the same. The main goal is to get rid of the entire arm64 port’s sources, while keeping intact the 32-bit ARM port and 64-bit aarch64 port.

Java 12 makes the world of programming even better with these new and significant changes. In addition to boosting application performance, Java 12 offers a wide new range of added on functionalities. Read our latest articles to find out how Java 12 forms a new paradigm to sweep the application development world! To know how you can embrace the power of the latest JAVA trends for your business, get in touch with our custom software development experts today!


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    About the Author

    Girish R

    Girish R, Programmer for 17 yrs, Blogger at, LifeHacker, DIYer. He loves to write about technology, Open source & gadgets. He currently leads the mobile app development team at Fingent.

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