Tuesday Mar 03, 2015

JDK 8u40 Released!

JDK 8u40 has been released and is available from the Java SE Downloads page. See the JDK 8u40 Update Release Notes for details.

Java Tutorial Updates

The Java Tutorial has been updated to include a new lesson in the Deployment trail that describes how to use the Java packaging tools to generate self-contained applications. Self-contained applications are Java applications that are bundled with the JRE that is needed to run. These applications are installed on a user's local drive and launched in the same way as native applications. See Deploying Self-Contained Applications for more information.

JDK Tools Enhancements

JDK 8u40 contains many tools enhancements. See Tools Enhancements in JDK 8 for details.

JavaFX Enhancements

Starting with the JDK 8u40 release, JavaFX controls are enhanced to support assistive technologies, meaning that JavaFX controls are now accessible. In addition, a public API is provided to allow developers to write their own accessible controls.

Accessibility support is provided on Windows and Mac OS X platforms and includes:

  • Support for reading JavaFX controls by a screen reader
  • JavaFX controls are traversable using the keyboard
  • Support for a special high-contrast mode that makes controls more visible to users.

JDK 8u40 also includes new JavaFX UI controls; a spinner control, formatted-text support, and a standard set of alert dialogs.

Spinner Control

A Spinner is a single line text field that lets the user select a number or an object value from an ordered sequence. See javafx.scene.control.Spinner class for more information.

Formatted Text

A new TextFormatter class provides text formatting capablity for subclasses of TextInputControl (for example, TextField and TextArea). See javafx.scene.control.TextFormatter class for more information.


The Dialog class allows applications to create their own custom dialogs. In addition, an an Alert class is also provided, that extends Dialog, and provides support for a number of pre-built dialog types that can be easily shown to users to prompt for a response. See javafx.scene.control.Dialog, javafx.scene.control.Alert, javafx.scene.control.TextInputDialog, and javafx.scene.control.ChoiceDialog classes for more information.

Commercial Features

Application Class Data Sharing (AppCDS):

Application Class Data Sharing (AppCDS) extends CDS to enable you to place classes from the standard extensions directories and the application class path in the shared archive. This is a commercial feature and is no longer considered experimental (contrary to what is specified in the java tool documentation). See the -XX:+UseAppCDS option in the java launcher tool page.

Cooperative Memory Management

Starting with JDK 8u40, the notion of "memory pressure" has been added to the JDK. Memory pressure is a property that represents the total memory usage (RAM) on the system. The higher the memory pressure, the closer the system is to running out of memory.

As a reaction to increased memory pressure, the JDK will try to reduce its memory usage. This is mainly done by reducing the Java heap size. The actions the JDK will take to reduce memory usage may lead to reduced performance. This is an intentional choice.

The pressure level is provided by the application through a JMX MXBean using a scale from 0 (no pressure) to 10 (almost out of memory). To enable this feature, the jdk.management.cmm.SystemResourcePressureMXBean should be registered. The memory pressure is then set using the "MemoryPressure" attribute.

A new command line flag -XX:MemoryRestriction that takes one of the arguments 'none', 'low', 'medium', or 'high', is also available. This flag will set the initial pressure in the JDK and will work also in cases where the MXBean is not registered.

Cooperative Memory Management requires the G1 GC (-XX:+UseG1GC). This feature is not compatible with the flag -XX:+ExplicitGCInvokesConcurrent.

New Commercial Flags

Two new VM options are now available for commercial license holders:

  • -XX:+ResourceManagement
  • -XX:ResourceManagementSampleInterval=value (milliseconds)

For more information, see the java tool page.

New MSI Installer Documentation

The Microsoft Windows Installer (MSI) Enterprise JRE Installer Guide is now available. The MSI Enterprise JRE Installer requires a commercial license for use in production. To learn more about commercial features and how to enable them, visit http://www.oracle.com/technetwork/java/javaseproducts.

Java Flight Recorder(JFR) Enhancements

It is now possible to enable Java Flight Recorder at runtime. For details, see the Java Flight Recorder Runtime Guide. Java Flight Recorder requires a commercial license for use in production. To learn more about commercial features and how to enable them, visit http://www.oracle.com/technetwork/java/javaseproducts.

Troubleshooting Guide Updates

The Troubleshooting Guide has been updated with new content for Troubleshooting using JMC, Troubleshooting Memory Leaks using JFR, and Troubleshooting Performance Issues using JFR.

Thursday Oct 23, 2014

JMC and JFR Documentation

In case you missed it, the user guides for Java Mission Control and Java Flight Recorder have moved! As of JDK 8u20, links to the 5.4 and 5.3 versions of these docs can be found the JMC tab of the javacomponents page at: http://docs.oracle.com/javacomponents/jmc.htm.

Redirects from the old locations are in place, but please update your bookmarks accordingly!

Tuesday Aug 19, 2014

Java Components Landing Page and Documentation Updates

The new Java Components page provides access to the documentation for tools that are available for monitoring, managing, and testing Java applications. Documentation for the new versions of the following tools is available:

  • JavaTest Harness 4.6. The JavaTest harness is a general purpose, fully-featured, flexible, and configurable test harness that is suited for most types of unit testing. See the JavaTest tab for documentation.

  • SigTest 3.1. SigTest is a collection of tools that can be used to compare APIs and to measure the test coverage of an API. See the SigTest tab for documentation.

The following tools are part of Oracle Java SE Advanced and Oracle Java SE Suite.

  • Java Mission Control and Java Flight Control 5.4 are supported in JDK 8u20. Java Flight Recorder and Java Mission Control together create a complete tool chain to continuously collect low level and detailed runtime information enabling after-the-fact incident analysis. See the JMC tab for documentation.

  • Advanced Management Console 1.0 is a new tool that is now available. AMC can be used to view information about the Java applets and Java Web Start applications running in your enterprise, and create deployment rules and rule sets to manage the execution of these applications. See the AMC tab for documentation.

  • Usage Tracker tracks how Java Runtime Environments (JREs) are being used in your systems. See the Usage Tracker tab for documentation.

Tuesday Mar 25, 2014

Learn More About Monitoring and Management Improvements in JDK 8

For users of commercial packages Java SE Advanced and Java SE Suite, JDK 8 includes a new version of Java Mission Control (JMC) that introduces a number of improvements to monitoring and profiling the HotSpot VM. JMC is a powerful set of tools for managing a running application and JVM. You can use it to perform extensive analysis based on detailed monitoring and profiling data.

JMC 5.3.0 reintroduces the Diagnostic Commands tab. This tab can be used to remotely execute commands available via the jcmd utility.

Another big improvement is the addition of content types for attributes. This means that each attribute contains metadata about its physical quantity and units, which helps rendering the attribute values on graphs properly with little or no configuration.

In addition, a number of known issues have been fixed, increasing overall stability and performance

To learn more about JMC 5.3.0, see the JMC User's Guide.

Marcus Hirt has presented a screencast titled Introducing Java Mission Control 5.3.0 during the Java 8 Launch Webcast where new JMC features were discussed in more detail.

Tuesday Sep 24, 2013

JavaOne 2013: Oracle Java Mission Control

On Monday, September 23, Marcus Hirt (Oracle) gave his first presentation at JavaOne 2013 entitled Production-Time Profiling Out of the Box. He talked about the latest addition to JDK 7: Oracle Java Mission Control, a tool suite for low-overhead production-time profiling and diagnostics that originated with the JRockit Mission Control. As part of the convergence between the HotSpot and Oracle JRockit JVMs, Oracle Java Mission Control is now available in the HotSpot JDK.

For more information about Oracle Java Mission Control, see the JMC User's Guide.


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