Configure Java logging using the console

 

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Java logging provides a standard logging API for your applications. Before applications can log diagnostic information, specify how you want the server to handle log output and what level of logging you require.

 

Overview

Developing, deploying and maintaining applications are complex tasks. When an application encounters an unexpected condition, it might not be able to complete a requested operation. You might want the application to inform the administrator that the operation failed and tell the administrator why the operation failed. This information enables the administrator to take the proper corrective action. Application developers might need to gather detailed information that relates to the path of a running application to determine the root cause of a failure that is due to a code bug. The facilities that are used for these purposes are typically referred to as logging and tracing. For more information read Java logging.

Using the console, you can:

• Enable or disable a particular log, specify where log files are stored and how many log files are kept.

• Specify the level of detail in a log, and specify a format for log output.

• Set a log level for each logger.

You can change the log configuration statically or dynamically. Static configuration changes affect applications when you start or restart the appserver. Dynamic or run time configuration changes apply immediately.

When a log is created, the level value for that log is set from the configuration data. If no configuration data is available for a particular log name, the level for that log is obtained from the parent of the log. If no configuration data exists for the parent log, the parent of that log is checked, and so on up the tree, until a log with a non-null level value is found. When you change the level of a log, the change is propagated to the children of the log, which recursively propagates the change to their children, as necessary.

 

Procedure

1. Optional: See the Java documentation for the java.util.logging class for a full description of the syntax and the construction of logging methods.

2. Set the output properties for a log:

   1. In the navigation pane, click...

      Servers | Application Servers | server | Troubleshooting | Logging and tracing

   2. Click the name of a system log to configure (Diagnostic Trace, JVM Logs, Process Logs or IBM Service Logs).

   3. To make a static change to the system log configuration, click the Configuration tab. To change the configuration dynamically, click the Runtime tab.

   4. Change the properties for the selected log according to your needs.

   5. Click Apply.

   6. Click OK.

3. Set the logging levels for your logs:

   1. In the navigation pane, click...

      Servers | Application Servers | server | Troubleshooting | Logging and tracing | Change Log Detail levels

      

   2. To make a static change to the configuration, click the Configuration tab. A list of well-known components, packages, and groups is displayed. To change the configuration dynamically, click the Runtime tab. The list of components, packages, and groups displays all the components that are currently registered on the running server.

   3. Select a component, package, or group to set a logging level.

   4. Click Apply.

   5. Click OK.

4. To have static configuration changes take effect, stop then restart the appserver.

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Java logging

Log level settings

Loggers

Log handlers

Log levels

Log filters

Log formatters

Use loggers in an application

HTTP error and NCSA access log settings

Logger.properties file for configuring logger settings

Example: Sample security policy for logging