| /* | |
| * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved. | |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
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| * This code is free software; you can redistribute it and/or modify it | |
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| * 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 | |
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| * | |
| * 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. | |
| * | |
| * <P> | |
| * There are four main target uses of the logs: | |
| * </P> | |
| * | |
| * <OL> | |
| * <LI> <I>Problem diagnosis by end users and system administrators</I>. | |
| * 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. | |
| * | |
| * <LI> <I>Problem diagnosis by field service engineers</I>. 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. | |
| * | |
| * <LI> <I>Problem diagnosis by the development organization</I>. | |
| * 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. | |
| * | |
| * <LI> <I>Problem diagnosis by developers</I>. 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. | |
| * </OL> | |
| * | |
| * <p> | |
| * The key elements of this package include: | |
| * <UL> | |
| * <LI> <I>Logger</I>: The main entity on which applications make | |
| * logging calls. A Logger object is used to log messages | |
| * for a specific system or application | |
| * component. | |
| * <LI> <I>LogRecord</I>: Used to pass logging requests between the logging | |
| * framework and individual log handlers. | |
| * <LI> <I>Handler</I>: 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. | |
| * <LI> <I>Level</I>: 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. | |
| * <LI> <I>Filter</I>: 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. | |
| * | |
| * <LI> <I>Formatter</I>: 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. | |
| * </UL> | |
| * <P> | |
| * 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. | |
| * </P> | |
| * | |
| * <h2>Null Pointers</h2> | |
| * <p> | |
| * 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). | |
| * | |
| * <H2>Related Documentation</H2> | |
| * <P> | |
| * For an overview of control flow, | |
| * please refer to the | |
| * {@extLink logging_overview Java Logging Overview} | |
| * </P> | |
| * | |
| * @since 1.4 | |
| */ | |
| package java.util.logging; |