OpenJ9 VM messages

Messages are issued by the OpenJ9 virtual machine (VM) in response to certain conditions. Understanding what the messages mean can help you with problem determination.

Message categories

There are three main categories of message:

Information
Information messages provide information about VM processing. For example, a dump information message is typically issued when a dump agent requests a dump.
Warning
Warning messages are issued by the VM to indicate conditions that might need user intervention.
Error
Error messages are issued by the VM when normal processing cannot proceed, because of unexpected conditions.

OpenJ9 virtual machine messages have the following format:

    JVM<type><number><code>

where:

  • JVM is a standard prefix.
  • <type> refers to the VM subcomponent that issued the message.
  • <number> is a unique numerical number.
  • <code> is one of the following codes:
    • I - Information message
    • W - Warning message
    • E - Error message

These messages can help you with problem determination.

By default, all error and some information messages are routed to the system log and also written to stderr or stdout. The specific information messages are JVMDUMP039I, JVMDUMP032I, and JVMDUMP033I, which provide valuable additional information about dumps produced by the VM. To route additional message types to the system log, or turn off message logging to the system log, use the -Xlog option. The -Xlog option does not affect messages written to the standard error stream (stderr). See OpenJ9 command-line options.

Finding logged messages

Logged messages can be found in different locations, according to platform.

Finding AIX messages

On AIX®, messages are logged by the syslog daemon (/usr/sbin/syslogd). Logged messages are written to the syslog file that is configured in /etc/syslog.conf. If the syslog daemon is not running, logged messages are lost.

You can redirect messages from the syslog daemon to the AIX error log facility by performing the following configuration steps:

  1. Set up a redirect in the file syslog.conf so that syslog messages are sent to the error log, by adding the following line:
        user.debug errlog
  1. If syslogd is already running, reload the updated configuration by running the following command:
        refresh -s syslogd
  1. The updated configuration is used each time syslogd starts. 4. Use the AIX errpt command or the System Management Interface Tool (SMIT) to read the messages sent to the error log.

For more information about AIX logging, see: Error-logging overview.

Finding Linux messages

On Linux®, messages are logged by the syslog daemon. To find where messages are logged, check the syslog configuration file.

Finding macOS messages

On macOS®, messages are logged by the syslog daemon. However, on Sierra and High Sierra, syslog does not work. If /var/log/system.log is not available, Console.app can be used instead.

Finding Windows messages

On Windows™, messages are logged in the application events section of the event viewer.

Finding z/OS messages

On z/OS®, messages are sent to the operator console. To see the messages, go from the ispf panel to the sdsf panel, then open the log panel.

Obtaining detailed message descriptions

Detailed message information is available to help with problem diagnosis.

Understanding the warning or error message issued by the VM can help you diagnose problems. All warning and error messages issued by the VM are listed by type in the messages guide: IBM® VM messages.

The messages, error codes, and exit codes in this guide apply to multiple versions of the VM.

Note: If the VM fills all available memory, the message number might be produced without a description for the error that caused the problem. Look for the message number in the relevant section of the J9 VM Messages guide to see the message description and the additional information provided.