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 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
 <html>
 <body bgcolor="white">

 Provides the management interfaces for monitoring and management of the
 Java virtual machine and other components in the Java runtime.
 It allows both local and remote
 monitoring and management of the running Java virtual machine.
 <p>

 <h4><a name="MXBean">Platform MXBean</a></h4>
 <p>
 A platform MXBean is a <i>managed bean</i> that
 conforms to the <a href="../../../javax/management/package-summary.html">JMX</a>
 Instrumentation Specification and only uses a set of basic data types.
 Each platform MXBean is a {@link java.lang.management.PlatformManagedObject}
 with a unique
 {@linkplain java.lang.management.PlatformManagedObject#getObjectName name}.
 <p>
 <h4>ManagementFactory</h4>

 <p>The {@link java.lang.management.ManagementFactory} class is the management
 factory class for the Java platform.  This class provides a set of
 static factory methods to obtain the MXBeans for the Java platform
 to allow an application to access the MXBeans directly.

 <p>A <em>platform MBeanServer</em> can be accessed with the
 {@link java.lang.management.ManagementFactory#getPlatformMBeanServer
  getPlatformMBeanServer} method.  On the first call to this method,
 it creates the platform MBeanServer and registers all platform MXBeans
 including {@linkplain java.lang.management.PlatformManagedObject
 platform MXBeans}.
 Each platform MXBean is registered with a unique name defined in
 the specification of the management interface.
 This is a single MBeanServer that can be shared by different managed
 components running within the same Java virtual machine.

 <h4>Interoperability</h4>

 <p>A management application and a platform MBeanServer of a running
 virtual machine can interoperate
 without requiring classes used by the platform MXBean interfaces.
 The data types being transmitted between the JMX connector
 server and the connector client are JMX
 {@linkplain javax.management.openmbean.OpenType open types} and
 this allows interoperation across versions.
 A data type used by the MXBean interfaces are mapped to an
 open type when being accessed via MBeanServer interface.
 See the <a href="../../../javax/management/MXBean.html#MXBean-spec">
 MXBean</a> specification for details.

 <h4><a name="examples">Ways to Access MXBeans</a></h4>

 <p>An application can monitor the instrumentation of the
 Java virtual machine and the runtime in the following ways:
 <p>
 <b>1. Direct access to an MXBean interface</b>
 <p>
 <ul>
 <li>Get an MXBean instance locally in the running Java virtual machine:<p>
 <pre>
    RuntimeMXBean mxbean = ManagementFactory.getRuntimeMXBean();

    // Get the standard attribute "VmVendor"
    String vendor = mxbean.getVmVendor();
 </pre>
 <p>Or by calling the
         {@link java.lang.management.ManagementFactory#getPlatformMXBean(Class)
                getPlatformMXBean} or
         {@link java.lang.management.ManagementFactory#getPlatformMXBeans(Class)
                getPlatformMXBeans} method:
 <pre>
    RuntimeMXBean mxbean = ManagementFactory.getPlatformMXBean(RuntimeMXBean.class);

    // Get the standard attribute "VmVendor"
    String vendor = mxbean.getVmVendor();
 </pre>
 <p>
 </li>
 <li>Construct an MXBean proxy instance that forwards the
     method calls to a given MBeanServer:<p>
 <pre>
    MBeanServerConnection mbs;

    // Connect to a running JVM (or itself) and get MBeanServerConnection
    // that has the JVM MBeans registered in it
    ...

    // Get a MBean proxy for RuntimeMXBean interface
    RuntimeMXBean proxy =
        {@link java.lang.management.ManagementFactory#getPlatformMXBean(MBeanServerConnection, Class)
        ManagementFactory.getPlatformMXBean}(mbs,
                                            RuntimeMXBean.class);
    // Get standard attribute "VmVendor"
    String vendor = proxy.getVmVendor();
 </pre>
 <p>A proxy is typically used to access an MXBean
    in a remote Java virtual machine.
    An alternative way to create an MXBean proxy is:
 <pre>
    RuntimeMXBean proxy =
        {@link java.lang.management.ManagementFactory#newPlatformMXBeanProxy
               ManagementFactory.newPlatformMXBeanProxy}(mbs,
                                                 ManagementFactory.RUNTIME_MXBEAN_NAME,
                                                 RuntimeMXBean.class);
 </pre>
 </li>
 </ul>
 <p>
 <b>2. Indirect access to an MXBean interface via MBeanServer</b><p>
 <ul>
 <li>Go through the
     {@link java.lang.management.ManagementFactory#getPlatformMBeanServer
     platform MBeanServer} to access MXBeans locally or
     a specific {@code MBeanServerConnection} to access
     MXBeans remotely.
     The attributes and operations of an MXBean use only
     <em>JMX open types</em> which include basic data types,
     {@link javax.management.openmbean.CompositeData CompositeData},
     and {@link javax.management.openmbean.TabularData TabularData}
     defined in {@link javax.management.openmbean.OpenType OpenType}.<p>
 <pre>
    MBeanServerConnection mbs;

    // Connect to a running JVM (or itself) and get MBeanServerConnection
    // that has the JVM MXBeans registered in it
    ...

    try {
        // Assuming the RuntimeMXBean has been registered in mbs
        ObjectName oname = new ObjectName(ManagementFactory.RUNTIME_MXBEAN_NAME);

        // Get standard attribute "VmVendor"
        String vendor = (String) mbs.getAttribute(oname, "VmVendor");
    } catch (....) {
        // Catch the exceptions thrown by ObjectName constructor
        // and MBeanServer.getAttribute method
        ...
    }
 </pre>
 </li>
 </ul>


 <h4><a name="extension">Platform Extension</a></h4>

 <p>A Java virtual machine implementation may add its platform extension to
 the management interface by defining platform-dependent
 interfaces that extend the standard management interfaces to include
 platform-specific metrics and management operations.
 The static factory methods in the <tt>ManagementFactory</tt> class will
 return the MXBeans with the platform extension.

 <p>
 It is recommended to name the platform-specific attributes with
 a vendor-specific prefix such as the vendor's name to
 avoid collisions of the attribute name between the future extension
 to the standard management interface and the platform extension.
 If the future extension to the standard management interface defines
 a new attribute for a management interface and the attribute name
 is happened to be same as some vendor-specific attribute's name,
 the applications accessing that vendor-specific attribute would have
 to be modified to cope with versioning and compatibility issues.

 <p>Below is an example showing how to access an attribute
 from the platform extension:

 <p>
 1) Direct access to the Oracle-specific MXBean interface
 <blockquote>
 <pre>
    List&lt;com.sun.management.GarbageCollectorMXBean&gt; mxbeans =
        ManagementFactory.getPlatformMXBeans(com.sun.management.GarbageCollectorMXBean.class);

    for (com.sun.management.GarbageCollectorMXBean gc : mxbeans) {
        // Get the standard attribute "CollectionCount"
        String count = mxbean.getCollectionCount();

        // Get the platform-specific attribute "LastGcInfo"
        GcInfo gcinfo = gc.getLastGcInfo();
        ...
    }
 </pre>
 </blockquote>

 <p>
 2) Access the Oracle-specific MXBean interface via <tt>MBeanServer</tt>
    through proxy

 <blockquote><pre>
    MBeanServerConnection mbs;

    // Connect to a running JVM (or itself) and get MBeanServerConnection
    // that has the JVM MXBeans registered in it
    ...

    List&lt;com.sun.management.GarbageCollectorMXBean&gt; mxbeans =
        ManagementFactory.getPlatformMXBeans(mbs, com.sun.management.GarbageCollectorMXBean.class);

    for (com.sun.management.GarbageCollectorMXBean gc : mxbeans) {
        // Get the standard attribute "CollectionCount"
        String count = mxbean.getCollectionCount();

        // Get the platform-specific attribute "LastGcInfo"
        GcInfo gcinfo = gc.getLastGcInfo();
        ...
    }
 </pre></blockquote>

 <p> Unless otherwise noted, passing a <tt>null</tt> argument to a constructor
 or method in any class or interface in this package will cause a {@link
 java.lang.NullPointerException NullPointerException} to be thrown.

 <p> The java.lang.management API is thread-safe.

 @see <a href="../../../javax/management/package-summary.html">
      JMX Specification.</a>

 @author  Mandy Chung
 @since   1.5

 </body>
 </html>
	<!--
	Copyright (c) 2003, 2006, Oracle and/or its affiliates. All rights reserved.
	DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

	This code is free software; you can redistribute it and/or modify it
	under the terms of the GNU General Public License version 2 only, as
	published by the Free Software Foundation. Oracle designates this
	particular file as subject to the "Classpath" exception as provided
	by Oracle in the LICENSE file that accompanied this code.

	This code is distributed in the hope that it will be useful, but WITHOUT
	ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	version 2 for more details (a copy is included in the LICENSE file that
	accompanied this code).

	You should have received a copy of the GNU General Public License version
	2 along with this work; if not, write to the Free Software Foundation,
	Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

	Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	or visit www.oracle.com if you need additional information or have any
	questions.
	-->

	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
	<html>
	<body bgcolor="white">

	Provides the management interfaces for monitoring and management of the
	Java virtual machine and other components in the Java runtime.
	It allows both local and remote
	monitoring and management of the running Java virtual machine.
	<p>

	<h4><a name="MXBean">Platform MXBean</a></h4>
	<p>
	A platform MXBean is a <i>managed bean</i> that
	conforms to the <a href="../../../javax/management/package-summary.html">JMX</a>
	Instrumentation Specification and only uses a set of basic data types.
	Each platform MXBean is a {@link java.lang.management.PlatformManagedObject}
	with a unique
	{@linkplain java.lang.management.PlatformManagedObject#getObjectName name}.
	<p>
	<h4>ManagementFactory</h4>

	<p>The {@link java.lang.management.ManagementFactory} class is the management
	factory class for the Java platform. This class provides a set of
	static factory methods to obtain the MXBeans for the Java platform
	to allow an application to access the MXBeans directly.

	<p>A <em>platform MBeanServer</em> can be accessed with the
	{@link java.lang.management.ManagementFactory#getPlatformMBeanServer
	getPlatformMBeanServer} method. On the first call to this method,
	it creates the platform MBeanServer and registers all platform MXBeans
	including {@linkplain java.lang.management.PlatformManagedObject
	platform MXBeans}.
	Each platform MXBean is registered with a unique name defined in
	the specification of the management interface.
	This is a single MBeanServer that can be shared by different managed
	components running within the same Java virtual machine.

	<h4>Interoperability</h4>

	<p>A management application and a platform MBeanServer of a running
	virtual machine can interoperate
	without requiring classes used by the platform MXBean interfaces.
	The data types being transmitted between the JMX connector
	server and the connector client are JMX
	{@linkplain javax.management.openmbean.OpenType open types} and
	this allows interoperation across versions.
	A data type used by the MXBean interfaces are mapped to an
	open type when being accessed via MBeanServer interface.
	See the <a href="../../../javax/management/MXBean.html#MXBean-spec">
	MXBean</a> specification for details.

	<h4><a name="examples">Ways to Access MXBeans</a></h4>

	<p>An application can monitor the instrumentation of the
	Java virtual machine and the runtime in the following ways:
	<p>
	<b>1. Direct access to an MXBean interface</b>
	<p>
	<ul>
	<li>Get an MXBean instance locally in the running Java virtual machine:<p>
	<pre>
	RuntimeMXBean mxbean = ManagementFactory.getRuntimeMXBean();

	// Get the standard attribute "VmVendor"
	String vendor = mxbean.getVmVendor();
	</pre>
	<p>Or by calling the
	{@link java.lang.management.ManagementFactory#getPlatformMXBean(Class)
	getPlatformMXBean} or
	{@link java.lang.management.ManagementFactory#getPlatformMXBeans(Class)
	getPlatformMXBeans} method:
	<pre>
	RuntimeMXBean mxbean = ManagementFactory.getPlatformMXBean(RuntimeMXBean.class);

	// Get the standard attribute "VmVendor"
	String vendor = mxbean.getVmVendor();
	</pre>
	<p>
	</li>
	<li>Construct an MXBean proxy instance that forwards the
	method calls to a given MBeanServer:<p>
	<pre>
	MBeanServerConnection mbs;

	// Connect to a running JVM (or itself) and get MBeanServerConnection
	// that has the JVM MBeans registered in it
	...

	// Get a MBean proxy for RuntimeMXBean interface
	RuntimeMXBean proxy =
	{@link java.lang.management.ManagementFactory#getPlatformMXBean(MBeanServerConnection, Class)
	ManagementFactory.getPlatformMXBean}(mbs,
	RuntimeMXBean.class);
	// Get standard attribute "VmVendor"
	String vendor = proxy.getVmVendor();
	</pre>
	<p>A proxy is typically used to access an MXBean
	in a remote Java virtual machine.
	An alternative way to create an MXBean proxy is:
	<pre>
	RuntimeMXBean proxy =
	{@link java.lang.management.ManagementFactory#newPlatformMXBeanProxy
	ManagementFactory.newPlatformMXBeanProxy}(mbs,
	ManagementFactory.RUNTIME_MXBEAN_NAME,
	RuntimeMXBean.class);
	</pre>
	</li>
	</ul>
	<p>
	<b>2. Indirect access to an MXBean interface via MBeanServer</b><p>
	<ul>
	<li>Go through the
	{@link java.lang.management.ManagementFactory#getPlatformMBeanServer
	platform MBeanServer} to access MXBeans locally or
	a specific {@code MBeanServerConnection} to access
	MXBeans remotely.
	The attributes and operations of an MXBean use only
	<em>JMX open types</em> which include basic data types,
	{@link javax.management.openmbean.CompositeData CompositeData},
	and {@link javax.management.openmbean.TabularData TabularData}
	defined in {@link javax.management.openmbean.OpenType OpenType}.<p>
	<pre>
	MBeanServerConnection mbs;

	// Connect to a running JVM (or itself) and get MBeanServerConnection
	// that has the JVM MXBeans registered in it
	...

	try {
	// Assuming the RuntimeMXBean has been registered in mbs
	ObjectName oname = new ObjectName(ManagementFactory.RUNTIME_MXBEAN_NAME);

	// Get standard attribute "VmVendor"
	String vendor = (String) mbs.getAttribute(oname, "VmVendor");
	} catch (....) {
	// Catch the exceptions thrown by ObjectName constructor
	// and MBeanServer.getAttribute method
	...
	}
	</pre>
	</li>
	</ul>


	<h4><a name="extension">Platform Extension</a></h4>

	<p>A Java virtual machine implementation may add its platform extension to
	the management interface by defining platform-dependent
	interfaces that extend the standard management interfaces to include
	platform-specific metrics and management operations.
	The static factory methods in the <tt>ManagementFactory</tt> class will
	return the MXBeans with the platform extension.

	<p>
	It is recommended to name the platform-specific attributes with
	a vendor-specific prefix such as the vendor's name to
	avoid collisions of the attribute name between the future extension
	to the standard management interface and the platform extension.
	If the future extension to the standard management interface defines
	a new attribute for a management interface and the attribute name
	is happened to be same as some vendor-specific attribute's name,
	the applications accessing that vendor-specific attribute would have
	to be modified to cope with versioning and compatibility issues.

	<p>Below is an example showing how to access an attribute
	from the platform extension:

	<p>
	1) Direct access to the Oracle-specific MXBean interface
	<blockquote>
	<pre>
	List<com.sun.management.GarbageCollectorMXBean> mxbeans =
	ManagementFactory.getPlatformMXBeans(com.sun.management.GarbageCollectorMXBean.class);

	for (com.sun.management.GarbageCollectorMXBean gc : mxbeans) {
	// Get the standard attribute "CollectionCount"
	String count = mxbean.getCollectionCount();

	// Get the platform-specific attribute "LastGcInfo"
	GcInfo gcinfo = gc.getLastGcInfo();
	...
	}
	</pre>
	</blockquote>

	<p>
	2) Access the Oracle-specific MXBean interface via <tt>MBeanServer</tt>
	through proxy

	<blockquote><pre>
	MBeanServerConnection mbs;

	// Connect to a running JVM (or itself) and get MBeanServerConnection
	// that has the JVM MXBeans registered in it
	...

	List<com.sun.management.GarbageCollectorMXBean> mxbeans =
	ManagementFactory.getPlatformMXBeans(mbs, com.sun.management.GarbageCollectorMXBean.class);

	for (com.sun.management.GarbageCollectorMXBean gc : mxbeans) {
	// Get the standard attribute "CollectionCount"
	String count = mxbean.getCollectionCount();

	// Get the platform-specific attribute "LastGcInfo"
	GcInfo gcinfo = gc.getLastGcInfo();
	...
	}
	</pre></blockquote>

	<p> Unless otherwise noted, passing a <tt>null</tt> argument to a constructor
	or method in any class or interface in this package will cause a {@link
	java.lang.NullPointerException NullPointerException} to be thrown.

	<p> The java.lang.management API is thread-safe.

	@see <a href="../../../javax/management/package-summary.html">
	JMX Specification.</a>

	@author Mandy Chung
	@since 1.5

	</body>
	</html>