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Monitoring and Management API Enhancements

The Java Platform, Standard Edition (Java SE) provides an API to allow you to monitor and manage the Java Virtual Machine (Java VM) and other applications, in the package java.lang.management.

The Java SE 6 platform includes the following enhancements to this API.

• Support for java.util.concurrent locks has been added.

  The ThreadMXBean.getThreadInfo methods have been enhanced to report the java.util.concurrent.locks.AbstractOwnableSynchronizer that a thread is waiting to acquire. The Java 2 Platform, Standard Edition (J2SE) 5.0 only reported an object monitor that a thread was blocked from entering or waiting to acquire.

  In addition, the following new methods have been added in the ThreadMXBean interface:

• • isObjectMonitorUsageSupported()
  • isSynchronizerUsageSupported()
  • findDeadlockedThreads()
• New classes and methods for obtaining the list of locks owned by a thread and to report which stack frame locked a monitor have been added to the java.lang.management package.
  • New LockInfo class.
  • New MonitorInfo class.
  • New ThreadInfo methods getLockInfo(), getLockedMonitors() and getLockedSynchronizers().
  • New ThreadMXBean methods dumpAllThreads() and getThreadInfo(long[] ids, boolean lockedMonitor, boolean lockedSynchronizers)
• A new method, getSystemLoadAverage(), has been added to OperatingSystemMXBean to return the system load average.

JConsole Enhancements

The Java SE platform provides a graphical monitoring tool called JConsole. The JConsole tool implements the Java Management Extensions (JMX) API and enables you to monitor the performance of a Java VM and any instrumented applications. Introduced in J2SE 5.0, JConsole became an officially supported feature of Java SE 6.

Some of the enhancements that have been made to the JConsole tool between these two releases are as follows.

• JConsole Plugin support, that allows you to build your own plug-ins to run with JConsole, for example, to add a custom tab for accessing your applications' MBeans.
• Dynamic attach capability, allowing you to connect JConsole to any application that supports the dynamic Attach API, that was also added in Java SE 6.
• Enhanced user interface that makes data more easily accessible.
• New Overview and VM Summary tabs, for a better presentation of general information about your Java VM.
• The HotSpot Diagnostic MBean, which provides an API to request heap dump at runtime and also change the setting of certain VM options.
• Improved presentation of MBeans, to make it easier to access your MBeans' operations and attributes.

Out-of-the-Box Remote Management Enhancements

The Java Java VM has built-in instrumentation that enables you to monitor and manage it using the JMX technology. These built-in management utilities are often referred to as out-of-the-box management tools for the Java VM. The following enhancement has been made to the out-of-the-box management utilities in this release.

• The remote method invocation (RMI) registry has been secured using the secure sockets layer (SSL). A new management property, com.sun.management.jmxremote.registry.ssl, has been added to enable the use of a SSL-enabled RMI registry so that only legimate clients with the appropriate SSL certificates can obtain the connector stub.

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