Java Doc for ManagementFactory.java in  » 6.0-JDK-Core » lang » java » lang » management » Java Source Code / Java DocumentationJava Source Code and Java Documentation

An application can access a platform MXBean in the following ways:

• Direct access to an MXBean interface
  1. Get the MXBean instance through the static factory method and access the MXBean locally of the running virtual machine.
  2. Construct an MXBean proxy instance that forwards the method calls to a given MBeanServer MBeanServer by calling ManagementFactory.newPlatformMXBeanProxy newPlatfromMXBeanProxy . A proxy is typically constructed to remotely access an MXBean of another running virtual machine.
• Indirect access to an MXBean interface via MBeanServer
  1. Go through the ManagementFactory.getPlatformMBeanServer platform MBeanServer to access MXBeans locally or a specific MBeanServerConnection to access MXBeans remotely. The attributes and operations of an MXBean use only JMX open types which include basic data types, javax.management.openmbean.CompositeData CompositeData , and javax.management.openmbean.TabularData TabularData defined in javax.management.openmbean.OpenType OpenType . The mapping is specified below.

Platform MXBeans

The platform MXBean interfaces use only the following data types:

• Primitive types such as int, long, boolean, etc
• Wrapper classes for primitive types such as java.lang.Integer Integer , java.lang.Long Long , java.lang.Boolean Boolean , etc and java.lang.String String
• java.lang.Enum Enum classes
• Classes that define only getter methods and define a static from method with a javax.management.openmbean.CompositeData CompositeData argument to convert from an input CompositeData to an instance of that class
• java.util.List List<E> where E is a primitive type, a wrapper class, an enum class, or a class supporting conversion from a CompositeData to its class
• java.util.Map Map<K,V> where K and V are a primitive type, a wrapper class, an enum class, or a class supporting conversion from a CompositeData to its class

When an attribute or operation of a platform MXBean is accessed via an MBeanServer, the data types are mapped as follows:

• A primitive type or a wrapper class is mapped to the same type.
• An Enum is mapped to String whose value is the name of the enum constant.
• A class that defines only getter methods and a static from method with a javax.management.openmbean.CompositeData CompositeData argument is mapped to javax.management.openmbean.CompositeData CompositeData .
• Map<K,V> is mapped to javax.management.openmbean.TabularData TabularData whose row type is a javax.management.openmbean.CompositeType CompositeType with two items whose names are "key" and "value" and the item types are the corresponding mapped type of K and V respectively and the "key" is the index.
• List<E> is mapped to an array with the mapped type of E as the element type.
• An array of element type E is mapped to an array of the same dimenions with the mapped type of E as the element type.

For example, the MemoryMXBean interface has the following getter and setter methods:

 public MemoryUsage getHeapMemoryUsage();
 public boolean isVerbose();
 public void setVerbose(boolean value);
 

Attribute Name	Type
HeapMemoryUsage	MemoryUsage.from CompositeData representing MemoryUsage
Verbose	boolean

MXBean Names

Management Interface	ObjectName
ClassLoadingMXBean	ManagementFactory.CLASS_LOADING_MXBEAN_NAMEjava.lang:type=ClassLoading
MemoryMXBean	ManagementFactory.MEMORY_MXBEAN_NAMEjava.lang:type=Memory
ThreadMXBean	ManagementFactory.THREAD_MXBEAN_NAMEjava.lang:type=Threading
RuntimeMXBean	ManagementFactory.RUNTIME_MXBEAN_NAMEjava.lang:type=Runtime
OperatingSystemMXBean	ManagementFactory.OPERATING_SYSTEM_MXBEAN_NAMEjava.lang:type=OperatingSystem

A Java virtual machine has zero or a single instance of the following management interfaces.

Management Interface	ObjectName
CompilationMXBean	ManagementFactory.COMPILATION_MXBEAN_NAMEjava.lang:type=Compilation

A Java virtual machine may have one or more instances of the following management interfaces.

Management Interface	ObjectName
GarbageCollectorMXBean	ManagementFactory.GARBAGE_COLLECTOR_MXBEAN_DOMAIN_TYPEjava.lang:type=GarbageCollector ,name=collector's name
MemoryManagerMXBean	ManagementFactory.MEMORY_MANAGER_MXBEAN_DOMAIN_TYPEjava.lang:type=MemoryManager ,name=manager's name
MemoryPoolMXBean	ManagementFactory.MEMORY_POOL_MXBEAN_DOMAIN_TYPEjava.lang:type=MemoryPool ,name=pool's name

MXBeans that get created and destroyed dynamically, for example, memory MemoryPoolMXBean pools and MemoryManagerMXBean managers , will automatically be registered and deregistered into the platform MBeanServer.

If the system property javax.management.builder.initial is set, the platform MBeanServer creation will be done by the specified javax.management.MBeanServerBuilder .

It is recommended that this platform MBeanServer also be used to register other application managed beans besides the platform MXBeans.

This method is equivalent to:

java.lang.reflect.Proxy.newProxyInstance Proxy.newProxyInstance (mxbeanInterface.getClassLoader(), new Class[] { mxbeanInterface }, handler)

MXBeans that get created and destroyed dynamically, for example, memory MemoryPoolMXBean pools and MemoryManagerMXBean managers , will automatically be registered and deregistered into the platform MBeanServer.

If the system property javax.management.builder.initial is set, the platform MBeanServer creation will be done by the specified javax.management.MBeanServerBuilder .

It is recommended that this platform MBeanServer also be used to register other application managed beans besides the platform MXBeans. This will allow all MBeans to be published through the same MBeanServer and hence allow for easier network publishing and discovery. Name conflicts with the platform MXBeans should be avoided. the platform MBeanServer; the platformMXBeans are registered into the platform MBeanServerat the first time this method is called.
exception:
  SecurityException - if there is a security manager and the caller does not have the permission required by javax.management.MBeanServerFactory.createMBeanServer.
See Also:   javax.management.MBeanServerFactory
See Also:   javax.management.MBeanServerFactory.createMBeanServer

This method is equivalent to:

java.lang.reflect.Proxy.newProxyInstance Proxy.newProxyInstance (mxbeanInterface.getClassLoader(), new Class[] { mxbeanInterface }, handler)

If the MXBean is a notification emitter (i.e., it implements javax.management.NotificationEmitter NotificationEmitter ), both the mxbeanInterface and NotificationEmitter will be implemented by this proxy.

Notes:

1. Using an MXBean proxy is a convenience remote access to a platform MXBean of a running virtual machine. All method calls to the MXBean proxy are forwarded to an MBeanServerConnection where java.io.IOException IOException may be thrown when the communication problem occurs with the connector server. An application remotely accesses the platform MXBeans using proxy should prepare to catch IOException as if accessing with the MBeanServerConnector interface.
2. When a client application is designed to remotely access MXBeans for a running virtual machine whose version is different than the version on which the application is running, it should prepare to catch java.io.InvalidObjectException InvalidObjectException which is thrown when an MXBean proxy receives a name of an enum constant which is missing in the enum class loaded in the client application.
3. javax.management.MBeanServerInvocationHandlerMBeanServerInvocationHandler or its javax.management.MBeanServerInvocationHandler.newProxyInstancenewProxyInstance method cannot be used to create a proxy for a platform MXBean. The proxy object created by MBeanServerInvocationHandler does not handle the properties of the platform MXBeans described in the class specification.

• mxbeanName is not with a valid ObjectName ObjectName format, or
• the named MXBean in the connection isnot a MXBean provided by the platform, or
• the named MXBean is not registered in the MBeanServerConnection, or
• the named MXBean is not an instance of the given mxbeanInterface