openj9.lang.management

Interface OpenJ9DiagnosticsMXBean

All Superinterfaces:

PlatformManagedObject

public interface OpenJ9DiagnosticsMXBean
extends PlatformManagedObject

This interface provides APIs to dynamically trigger dump agents. APIs are also available to configure dump options. This MXBean reuses the methods in com.ibm.jvm.Dump API

Usage example for the OpenJ9DiagnosticsMXBean

... try { mxbeanName = new ObjectName("openj9.lang.management:type=OpenJ9Diagnostics"); } catch (MalformedObjectNameException e) { // Exception Handling } try { MBeanServer mbeanServer = ManagementFactory.getPlatformMBeanServer(); if (false == mbeanServer.isRegistered(mxbeanName)) { // OpenJ9DiagnosticsMXBean not registered } OpenJ9DiagnosticsMXBean diagBean = JMX.newMXBeanProxy(mbeanServer, mxbeanName, OpenJ9DiagnosticsMXBean.class); } catch (Exception e) { // Exception Handling }

Method Summary

Modifier and Type	Method and Description
String[]	queryDumpOptions() Returns the current dump configuration as an array of Strings, or null if an internal error occurs.
void	resetDumpOptions() Reset the JVM dump options to the settings specified when the JVM was started removing any additional configuration done since then.
void	setDumpOptions(String dumpOptions) This function sets options for the dump subsystem.
String	triggerClassicHeapDump() This function triggers the heap dump agent and requests for a heap dump in CLASSIC format.
void	triggerDump(String dumpAgent) This function triggers the specified dump agent.
String	triggerDumpToFile(String dumpAgent, String fileNamePattern) This function triggers the specified dump agent.

Methods inherited from interface java.lang.management.PlatformManagedObject

getObjectName

Method Detail

resetDumpOptions

void resetDumpOptions()
               throws ConfigurationUnavailableException

Reset the JVM dump options to the settings specified when the JVM was started removing any additional configuration done since then. This method may throw a ConfigurationUnavailableException if the dump configuration cannot be altered. If this occurs it will usually be because a dump event is currently being handled.

Throws:

ConfigurationUnavailableException - if the configuration cannot be changed because a dump is already in progress

SecurityException - if there is a security manager and it doesn't allow the checks required to change the dump settings

queryDumpOptions

String[] queryDumpOptions()

Returns the current dump configuration as an array of Strings, or null if an internal error occurs. The syntax of the option Strings is the same as the -Xdump command-line option, with the initial -Xdump: omitted. See the -Xdump option section on dump agents in the documentation for the OpenJ9 JVM.

Throws:

SecurityException - if there is a security manager and it doesn't allow the checks required to read the dump settings

setDumpOptions

void setDumpOptions(String dumpOptions)
             throws InvalidOptionException,
                    ConfigurationUnavailableException

This function sets options for the dump subsystem. The dump option is passed in as a String. Use the same syntax as the -Xdump command-line option, with the initial -Xdump: omitted. See the -Xdump option section on dump agents in the documentation for the OpenJ9 JVM. This method may throw a ConfigurationUnavailableException if the dump configuration cannot be altered.

Parameters:

dumpOptions - the options string to be set

Throws:

InvalidOptionException - if the specified dumpOptions cannot be set or is incorrect

ConfigurationUnavailableException - if the configuration cannot be changed because a dump is already in progress

SecurityException - if there is a security manager and it doesn't allow the checks required to change the dump settings

NullPointerException - if dumpOptions is null

triggerDump

void triggerDump(String dumpAgent)
          throws IllegalArgumentException

This function triggers the specified dump agent. Dump agents supported - java, snap, system and heap. A java dump is in a human-readable format, and summarizes the state of the JVM. The default heap dump format (a phd file) is not human-readable. A system dump is a platform-specific file that contains information about the active processes, threads, and system memory. System dumps are usually large. The snap dump format is not human-readable and must be processed using the trace formatting tool supplied with the OpenJ9 JVM.

Parameters:

dumpAgent - the dump agent to be triggered

Throws:

IllegalArgumentException - if the specified dump agent is invalid or unsupported by this method

RuntimeException - if the vm does not contain RAS dump support

SecurityException - if there is a security manager and it doesn't allow the checks required to trigger this dump

NullPointerException - if dumpAgent is null

triggerDumpToFile

String triggerDumpToFile(String dumpAgent,
                         String fileNamePattern)
                  throws IllegalArgumentException,
                         InvalidOptionException

This function triggers the specified dump agent. Dump agents supported - java, snap, system and heap. The JVM will attempt to write the file to the specified file name. This may include replacement tokens as documented in the section on dump agents in the documentation for the OpenJ9 JVM. A string containing the actual filename written to is returned. This may not be the same as the requested filename for several reasons:

• null or the empty string was specified, this will cause the JVM to write the dump to the default location based on the current dump settings and return that path.
• Replacement (%) tokens were specified in the file name. These will have been expanded.
• The full path is returned, if only a filename with no directory was specified the full path with the directory the dump was written to will be returned.
• The JVM couldn't write to the specified location. In this case it will attempt to write the dump to another location, unless -Xdump:nofailover was specified on the command line.

If a security manager exists a permission check for com.ibm.jvm.DumpPermission will be made, if this fails a SecurityException will be thrown.

Parameters:

dumpAgent - the dump agent to be triggered

fileNamePattern - the filename to write to, which may be null, empty or include replacement tokens

Returns:

the file name that the dump was actually written to

Throws:

InvalidOptionException - if the fileNamePattern was invalid

IllegalArgumentException - if the specified dump agent is invalid or unsupported by this method

SecurityException - if there is a security manager and it doesn't allow the checks required to trigger this dump

NullPointerException - if dumpAgent is null

triggerClassicHeapDump

String triggerClassicHeapDump()
                       throws InvalidOptionException

This function triggers the heap dump agent and requests for a heap dump in CLASSIC format.

Returns:

The file name of the dump that was created

Throws:

InvalidOptionException - if the dump operation fails

RuntimeException - if the JVM does not contain RAS dump support

SecurityException - if there is a security manager and it doesn't allow the checks required to trigger this dump