3.9. Logging settings

Logging provides a possibility to examine what the application is doing internally. This is primarily intended to be used for troubleshooting purposes. It requires a logging framework to be enabled to be operative.

By contrast, the configuration items verbose and debug can also be used to get some information about the running application, but these work without logging framework. The information provided by these two options however, is much more sparse and in the case of the verbose option intended for normal operation, not just troubleshooting.

Logging on the other hand provides a way to enable diagnostic output in a lot of places in the running code and allows to configure which of these messages should be displayed on a fine grained level of detail. The exact nature of what can be configured and the format of the configuration file is determined by the logging framework in use. For the specification of the format of these configuration files please refer to the documentation of the corresponding logging framework.

These are the possible options for the logging framework to be used:

The standard hardwired logging configuration will suppress all diagnostic output and just display warning and error messages to the console which started the application. Thus when starting the application in a windowing environment which doesn't provide a console, no output will ever be visible.

To change this behavior, a logging configuration file can be specified with the logging configuration item which by default specifies the file logging.properties in the current directory from which the application is being started. If such a file is found, it will be loaded and used to configure the logging framework in use. From that moment on, the logging messages should appear in the configured output appenders (console, log file, etc.).