JDK 1.4 Tutorial, eDoc 4 : Instrumenting Your Code with Logging Messages

There are a number of logging systems that have been created for Java, but lack of standardization has prevented them from reaching their full potential. JDK 1.4 comes complete with a new API that lets you log important run-time information from your Java program. It provides multiple detail levels and multiple configuration methods.

This e-doc will teach you how to get the most out of this new feature -- how to set up logging, and how to decide what information to log, and how. You'll also learn how to customize logging to suit your specific needs.

This e-doc will show you how to:

• Log message from your program
• Set up logging for a package
• Use different logging levels for different messages
• Create a custom Handler
• Create a custom Filter
• Create a custom Formatter
• Deal with logging efficiency issues
• Configure logging from a configuration file
• Configure logging from code

Sample programs included in this chapter:

• A chat (instant messaging) server with a full set of logging statements
• A GUI interface to the logging system
• A custom formatter that emits briefer messages