Sun GlassFish Message Queue 4.4 Developer's Guide for JMX Clients

JVM Monitor

Each broker has a single JVM monitor MBean, used for monitoring the Java Virtual Machine (JVM).


Note –

This MBean is useful only with the Java Development Kit (JDK) version 1.4 or lower. JDK version 1.5 includes built-in MBeans that provide more detailed information on the state of the JVM.


Object Name

The JVM monitor MBean has the following object name:

com.sun.messaging.jms.server:type=JVM,subtype=Monitor

A string representing this object name is defined as a static constant JVM_MONITOR_MBEAN_NAME in the utility class MQObjectName.

Attributes

The JVM monitor MBean has the attributes shown in Table 3–89. The names of these attributes are defined as static constants in the utility class JVMAttributes.

Table 3–89 JVM Monitor Attributes

Name 

Type 

Settable? 

Description 

TotalMemory

Long

No 

Current total memory, in bytes 

InitMemory

Long

No 

Initial heap size at JVM startup, in bytes

FreeMemory

Long

No 

Amount of memory currently available for use, in bytes 

MaxMemory

Long

No 

Maximum allowable heap size, in bytes 

Any memory allocation attempt that would exceed this limit will cause an OutOfMemoryError exception to be thrown.