/*
* Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
/**
* 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:
*
*
*
* - Problem diagnosis by end users and system administrators.
* This consists of simple logging of common problems that can be fixed
* or tracked locally, such as running out of resources, security failures,
* and simple configuration errors.
*
*
- Problem diagnosis by field service engineers. The logging information
* used by field service engineers may be considerably more complex and
* verbose than that required by system administrators. Typically such information
* will require extra logging within particular subsystems.
*
*
- Problem diagnosis by the development organization.
* When a problem occurs in the field, it may be necessary to return the captured logging
* information to the original development team for diagnosis. This logging
* information may be extremely detailed and fairly inscrutable. Such information might include
* detailed tracing on the internal execution of particular subsystems.
*
*
- Problem diagnosis by developers. The Logging APIs may also be
* used to help debug an application under development. This may
* include logging information generated by the target application
* as well as logging information generated by lower-level libraries.
* Note however that while this use is perfectly reasonable,
* the logging APIs are not intended to replace the normal debugging
* and profiling tools that may already exist in the development environment.
*
*
*
* The key elements of this package include:
*
* - Logger: The main entity on which applications make
* logging calls. A Logger object is used to log messages
* for a specific system or application
* component.
*
- LogRecord: Used to pass logging requests between the logging
* framework and individual log handlers.
*
- Handler: Exports LogRecord objects to a variety of destinations
* including memory, output streams, consoles, files, and sockets.
* A variety of Handler subclasses exist for this purpose. Additional Handlers
* may be developed by third parties and delivered on top of the core platform.
*
- Level: Defines a set of standard logging levels that can be used
* to control logging output. Programs can be configured to output logging
* for some levels while ignoring output for others.
*
- Filter: Provides fine-grained control over what gets logged,
* beyond the control provided by log levels. The logging APIs support a general-purpose
* filter mechanism that allows application code to attach arbitrary filters to
* control logging output.
*
*
- Formatter: Provides support for formatting LogRecord objects. This
* package includes two formatters, SimpleFormatter and
* XMLFormatter, for formatting log records in plain text
* or XML respectively. As with Handlers, additional Formatters
* may be developed by third parties.
*
*
* 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.
*
*
* Null Pointers
*
* 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).
*
*
Related Documentation
*
* For an overview of control flow,
* please refer to the
* Java Logging Overview
*
*
* @since 1.4
*/
package java.util.logging;