Provides the classes and interfaces of the Java™ 2 platform's core logging facilities. The central goal of the logging APIs is to support maintaining and servicing software at customer sites.
There are four main target uses of the logs:
The key elements of this package include:
The Logging APIs offer both static and dynamic configuration control. Static control enables field service staff to set up a particular configuration and then re-launch the application with the new logging settings. Dynamic control allows for updates to the logging configuration within a currently running program. The APIs also allow for logging to be enabled or disabled for different functional areas of the system. For example, a field service engineer might be interested in tracing all AWT events, but might have no interest in socket events or memory management.
In general, unless otherwise noted in the javadoc, methods and constructors will throw NullPointerException if passed a null argument. The one broad exception to this rule is that the logging convenience methods in the Logger class (the config, entering, exiting, fine, finer, finest, log, logp, logrb, severe, throwing, and warning methods) will accept null values for all arguments except for the initial Level argument (if any).
For an overview of control flow, please refer to the Java Logging Overview.
A Filter can be used to provide fine grain control over what is logged, beyond the control provided by log levels.
ErrorManager objects can be attached to Handlers to process any error that occurs on a Handler during Logging.
Simple file logging
A Formatter provides support for formatting LogRecords.
The Level class defines a set of standard logging levels that can be used to control logging output.
A Logger object is used to log messages for a specific system or application component.
The permission which the SecurityManager will check when code that is running with a SecurityManager calls one of the logging control methods (such as Logger.setLevel).
There is a single global LogManager object that is used to maintain a set of shared state about Loggers and log services.
LogRecord objects are used to pass logging requests between the logging framework and individual log Handlers.
Print a brief summary of the
Simple network logging
Stream based logging
Format a LogRecord into a standard XML format.
Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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