The default implementation of java.util.logging provided in the JDK is too limited to be useful. A limitation of JDK Logging appears to be the inability to have per-web application logging, as the configuration is per-VM. As a result, Tomcat will, in the default configuration, replace the default LogManager implementation with a container friendly implementation called JULI, which addresses these shortcomings. It supports the same configuration mechanisms as the standard JDK java.util.logging, using either a programmatic approach, or properties files. The main difference is that per-classloader properties files can be set (which enables easy redeployment friendly webapp configuration), and the properties files support slightly extended constructs which allows more freedom for defining handlers and assigning them to loggers.
JULI is enabled by default, and supports per classloader configuration, in addition to the regular global java.util.logging configuration. This means that logging can be configured at the following layers:
- In the JDK's logging.properties file. Check your JAVA_HOME environment setting to see which JDK Tomcat is using. The file will be in
$JAVA_HOME/jre/lib
. Alternately, it can also use a global configuration file located elsewhere by using the system property java.util.logging.config.file
, or programmatic configuration using java.util.logging.config.class
. - In each classloader using a logging.properties file. This means that it is possible to have a configuration for the Tomcat core, as well as separate configurations for each webapps which will have the same lifecycle as the webapps.
The default logging.properties specifies a ConsoleHandler for routing logging to stdout and also a FileHandler. A handler's log level threshold can be set using SEVERE, WARNING, INFO, CONFIG, FINE, FINER, FINEST or ALL. The logging.properties shipped with JDK is set to INFO. You can also target specific packages to collect logging from and specify a level. Here is how you would set debugging from Tomcat. You would need to ensure the ConsoleHandler's level is also set to collect this threshold, so FINEST or ALL should be set. Please refer to Sun's java.util.logging documentation for the complete details.
| | |
| org.apache.catalina.level=FINEST | |
| | |
The configuration used by JULI is extremely similar, but uses a few extensions to allow better flexibility in assigning loggers. The main differences are:
- A prefix may be added to handler names, so that multiple handlers of a single class may be instantiated. A prefix is a String which starts with a digit, and ends with '.'. For example,
22foobar.
is a valid prefix. - As in Java 6.0, loggers can define a list of handlers using the
loggerName.handlers
property. - By default, loggers will not delegate to their parent if they have associated handlers. This may be changed per logger using the
loggerName.useParentHandlers
property, which accepts a boolean value. - The root logger can define its set of handlers using a
.handlers
property. - Logging is not buffered by default. To configure buffering, use the
bufferSize
property of a handler. A value of 0
uses system default buffering (typically an 8K buffer will be used). A value of <0
forces a writer flush upon each log write. A value >0
uses a BufferedOutputStream with the defined value but note that the system default buffering will also be applied. - System property replacement is performed for property values which contain ${systemPropertyName}.
Example logging.properties file to be placed in $CATALINA_BASE/conf:
| | |
| handlers = 1catalina.org.apache.juli.FileHandler, 2localhost.org.apache.juli.FileHandler, 3manager.org.apache.juli.FileHandler, 4admin.org.apache.juli.FileHandler, java.util.logging.ConsoleHandler .handlers = 1catalina.org.apache.juli.FileHandler, java.util.logging.ConsoleHandler ############################################################ # Handler specific properties. # Describes specific configuration info for Handlers. ############################################################ 1catalina.org.apache.juli.FileHandler.level = FINE 1catalina.org.apache.juli.FileHandler.directory = ${catalina.base}/logs 1catalina.org.apache.juli.FileHandler.prefix = catalina. 2localhost.org.apache.juli.FileHandler.level = FINE 2localhost.org.apache.juli.FileHandler.directory = ${catalina.base}/logs 2localhost.org.apache.juli.FileHandler.prefix = localhost. 3manager.org.apache.juli.FileHandler.level = FINE 3manager.org.apache.juli.FileHandler.directory = ${catalina.base}/logs 3manager.org.apache.juli.FileHandler.prefix = manager. 4admin.org.apache.juli.FileHandler.level = FINE 4admin.org.apache.juli.FileHandler.directory = ${catalina.base}/logs 4admin.org.apache.juli.FileHandler.prefix = admin. 4admin.org.apache.juli.FileHandler.bufferSize = 16384 java.util.logging.ConsoleHandler.level = FINE java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter ############################################################ # Facility specific properties. # Provides extra control for each logger. ############################################################ org.apache.catalina.core.ContainerBase.[Catalina].[localhost].level = INFO org.apache.catalina.core.ContainerBase.[Catalina].[localhost].handlers = 2localhost.org.apache.juli.FileHandler org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/manager].level = INFO org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/manager].handlers = 3manager.org.apache.juli.FileHandler org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/admin].level = INFO org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/admin].handlers = 4admin.org.apache.juli.FileHandler # For example, set the com.xyz.foo logger to only log SEVERE # messages: #org.apache.catalina.startup.ContextConfig.level = FINE #org.apache.catalina.startup.HostConfig.level = FINE #org.apache.catalina.session.ManagerBase.level = FINE | |
| | |
Example logging.properties for the servlet-examples web application to be placed in WEB-INF/classes inside the web application:
| | |
| handlers = org.apache.juli.FileHandler, java.util.logging.ConsoleHandler ############################################################ # Handler specific properties. # Describes specific configuration info for Handlers. ############################################################ org.apache.juli.FileHandler.level = FINE org.apache.juli.FileHandler.directory = ${catalina.base}/logs org.apache.juli.FileHandler.prefix = servlet-examples. java.util.logging.ConsoleHandler.level = FINE java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter | |
| | |