Logging and tracing with Java logging
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 has 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.
Java logging is the logging toolkit provided by the java.util.logging package. Java logging provides a standard logging API for your applications.
Message logging (messages) and diagnostic trace (trace) are conceptually similar, but do have important differences. These differences are important for application developers to understand to use these tools properly. The following operational definitions of messages and trace are provided.
- Message
- A message entry is an informational record that is intended for end users, systems administrators, and support personnel to view. The text of the message must be clear, concise, and interpretable by an end user. Messages are typically localized, meaning they are displayed in the national language of the end user. Although the destination and lifetime of messages might be configurable, some level of message logging should be enabled in normal system operation. Message logging should be used judiciously because of performance considerations and the size of the message repository.
- Trace
- A trace entry is an information record that is intended for service engineers or developers to use. As such, a trace record might be considerably more complex, verbose and detailed than a message entry. Localization support is typically not used for trace entries. Trace entries can be fairly inscrutable, understandable only by the appropriate developer or service personnel. It is assumed that trace entries are not written during normal runtime operation, but can be enabled as needed to gather diagnostic information.
To use Java logging, see the following topics:
See the Java documentation for the java.util.logging class for a full description of the syntax and the construction of logging methods.
See also
Loggers
Log handlers
Log levels
Log filters
Log formatters
Configuring logging properties using the administrative console
Configuring logging properties for an application
Sample security
Using loggers in an application