Apache log4j 1.2

Release History

Version Date Description
1.2.16 2010-04-06 Maintenance release
1.2.15 2007-08-24 SyslogAppender enhancements, NTEventLogAppender and Maven build.
1.2.14 2006-09-18 AsyncAppender rewrite, Syslog and SMTPAppender enhancements.
1.2.13 2005-12-04 TRACE level missing info fixed, ConsoleAppender.follow added to make redirection following an optional behavior.
1.2.12 2005-08-29 TRACE level introduced, ConsoleAppender modified to follow redirection of System.out
1.2.11 2005-06-18 JMS MessageRenderer fix
1.2.10 2005-04-28 Version 1.2.10 was not released following the accepted rules and process of the log4j project and Logging Services Project and was recalled and removed. Please do not use version 1.2.10, it is not an official log4j release.
1.2.9 2004-11-01 Deprecation of obsolete methods
1.2.8 2003-02-19 Fixes to XMLAppender, DOMConfiguration, SocketAppender and JDBCAppender.
1.2.7 2002-10-09 log4j.xml now checked during default configuration.
1.2.6 2002-07-31 LoggingEvent.getLoggerName() added, JMSAppender enhancements.
1.2.5 2002-07-05 AsyncAppender.close now closes nested appender.
1.2.4 2002-06-12 XMLLayout now handles embedded CDATA, JDBCAppender deprecated.
1.2.3 2002-05-24 SyslogAppender and stack trace fixes.
1.2.2 2002-05-22 NULL added as synonym for INHERITED in Configurators, Thread context loader used preferentially.
1.2.1 2002-05-17 Fixed MDC problem when used with AsyncAppender
1.2 2002-05-01 Initial release of log4j 1.2
1.1.3 2001-06-19 Added missing namespace and reduced size of log4j-core.jar.
1.1.2 2001-06-07 Default initialization improvements
1.1.1 2001-05-20 Added custom priority support to PropertyConfigurator, SMTPAppender visibility changes.
1.1 2001-05-19 Minor documentation changes
1.1b7 2001-05-09
1.1b6 2001-04-26
1.1b5 2001-04-22
1.1b4 2001-04-20
1.1b3 2001-04-18
1.1b2 2001-04-18
1.1b1 2001-02-23
1.0.4 2001-01-12
1.0.3 2001-01-11
1.0.2 2001-01-11
1.0.1 2001-01-10
1.0 2001-01-08
0.9.1 2000-11-30 the 19th public release
0.9.0 2000-11-20 the 18th public release
0.8.5b 2000-08-27
0.8.5a 2000-08-24
0.8.5. 2000-08-23
0.8.4d 2000-05-11
0.8.4c 2000-05-05
0.8.4b 2000-05-03
0.8.4a 2000-05-03
0.8.4 2000-05-01
0.8.3b 2000-04-14
0.8.3a 2000-04-14
0.8.3 2000-04-13
0.8.2 2000-03-23
0.8.1 2000-02-19
0.8.0 2000-02-09
0.7.5 2000-01-29
0.7.4 2000-01-21
0.7.3 2000-01-14
0.7.2 2000-01-04
0.7.1 1999-12-20
0.7.0 1999-12-16
0.6.2 1999-12-08
0.6.1 1999-11-16
0.6.0 1999-11-09
0.5a 1999-10-28
0.5 1999-10-27
1999-10-15

Release 1.2.16 - 2010-04-06

Type Changes By
? log4j 1.2.16 release preparation. Fixes 43313.
? Create a public identifier for log4j.dtd ("-//APACHE//DTD LOG4J 1.2//EN") Fixes 42842.
? TelnetAppender misses messages when one of many clients disconnect. Fixes 44108.
? TelnetAppender throws null pointers at log time when socket couldn't be opened. Fixes 44109.
? ThrowableInformation.getThrowableStringRep can return null strings. Fixes 44032.
? log4j.dtd defines class attribute for category element, but not for logger. Fixes 43298.
? SMTPAppender.setSMTPUserName and others missing @since tags. Fixes 43314.
? Request for compile-on-Windows help file in src package. Fixes 43618.
? AsyncAppender failing on changing message objects. Fixes 43599.
? Subst-mechanism in DOMConfigurator broken. Fixes 43325.
? DailyRollingFileAppender may lose messages during failed rollover attempts. Fixes 43374.
? Fix mangled source-repository.html. Fixes 43312.
? Minor documentation changes. Fixes 43387.
? Make javamail, jmx, jms dependencies optional in pom.xml. Fixes 43304.
? SocketHubAppender should expose actual port in use to extending classes. Fixes 43874.
? SocketHubAppender in the 1.2.16 does not support a scroll back buffer or application property Fixes 44551.
? Give log4j threads reasonable names. Fixes 41156.
? LocationInfo can report wrong caller when other class names contain logger class name as substring. Fixes 44888.
? ErrorHandlerTestCase is not run and does not pass. Fixes 45426.
? Agent.java is sole dependency on jmxtools.jar with Java 5+. Fixes 45485.
? Eliminate compile dependency on non-redistributable JMS reference implementation. Fixes 44517.
? Exception in call to toString of message propagates to caller. Fixes 37182.
? Javadoc class index corrupted by JDBCAppender deprecation warning. Fixes 45299.
? Improve warning message when log4j is accessed after unload by Tomcat. Fixes 43867.
? NullPointerException in NDC.remove after unload by Tomcat. Fixes 45335.
? Configuring triggering/rolling policies should be supported through properties. Fixes 36384.
? More explanations when hitting WARN No appenders could be found for logger. Fixes 25747.
? Use Throwable.getStackTrace to obtain location when running on JDK 1.4 or later. Fixes 45039.
? AsyncAppender fails on changing Throwable. Fixes 44745.
? Extra NPE error message when using missing appender class with DOMConfigurator. Fixes 44899.
? org.apache.log4j.varia.NullAppender lacks static accessor to static instance. Fixes 44555.
? Javadoc for Appender.getName implies that the return value will be unique and not null. Fixes 43849.
? Weekly rotation problem in Europe. Fixes 40888.
? Add OSGi packaging info. Fixes 43282.
? InterruptedIOException ignored by log4j. Fixes 44157.
? HierarchyDynamicMBean missing unregister MBean Fixes 40246.
? Support -Dm2_repo option on Maven build for non-default Maven repository location. Fixes 45635.
? 2 tests for DateLayout are failing because of ill initialized DateFormat. Fixes 45636.
? Incorrect user mailing list URL. Fixes 45659.
? NTEventLogAppender.dll for 64-bit editions for Microsoft Windows. Fixes 44386.
? Add configuration of ThrowableRenderers and add org.apache.log4j.EnhancedThrowableRenderer. Fixes 45721.
? SMTPAppender does not force evaluation of message at request time Fixes 45969.
? Support SSL transport in SMTPAppender Fixes 25355.
? SMTPAppender should have a sendOnClose option Fixes 45980.
? Support %X layout specification to output all MDC key-value pairs Fixes 45982.
? Add replyTo attribute to SMTPAppender Fixes 45990.
? SMTPAppender does not properly encode subject or content containing non-ASCII characters. Fixes 44644.
? Clarify javadoc of Layout.ignoresThrowable. Fixes 46388.
? SyslogAppender.append throws exception if layout is not set. Fixes 46271.
? QuietWriter.write should check for null argument. Fixes 46144.
? LogFactor5 CategoryPath doesn't replace slashes with dots. Fixes 46512.
? LoggerDynamicMBean needs to handle a null Appender name. Fixes 46163.
? DOMConfigurator.configure(URL) fails on JRE 1.5.0_16. Fixes 45704.
? Document system properties used by log4j. Fixes 44357.
? log4j is susceptible to exceptions in Exception.printStackTrace. Fixes 44038.
? Misuse of "it's" in Javadoc for PatternLayout. Fixes 46741.
? Add SMTPAppender.formatBody to simplify extension. Fixes 47142.
? Failure when toString() of throwable performs logging in SocketAppender, SocketHubAppender and JDBCAppender. Fixes 46404.
? Reading configuration files from a JAR locks the JAR file Fixes 47465.
? PropertyConfigurator does not support configuring ErrorHandler. Fixes 38061.
? log4j.ignoreTCL should apply to the getResource method in addition to the loadClass method of org.apache.log4j.helpers.Loader. Fixes 47967.
? The QuietWriter class does not live up to its published contract. Fixes 46539.
? More Debug output for log4j auto-configure requested. Fixes 46983.
? Add MDC.clear(). Fixes 47107.
? NullPointerException when calling Category.removeAllAppenders(). Fixes 47547.
? Allow overriding of flush strategy. Fixes 28647.
? Add recommendation to use EnhancedPatternLayout to avoid synchronization issues in PatternLayout Fixes 47350.
? Source contains unnecessary imports. Fixes 45481.
? Add LoggingEvent.removeProperty Fixes 48159.
? Typo ("two three goals") in log4j FAQ Fixes 48187.
? Unit tests fail for system dates after 2009-12-31 Fixes 48531.
? Download page does not have link to KEYS file Fixes 48604.
? Add parameterized logging utility classes LogMF and LogSF from extras companion. Fixes 49812.
? Add EnhancedPatternLayout from extras companion. Fixes 48927.
? Links to example code broken in the JavaDocs Fixes 48784.
? Unused imports and variables in test code cause gcj compile warnings. Fixes 48953.
? Unit tests fail on Apache Harmony and gcj due to stack trace expectations. Fixes 49002.
? SocketServerTestCase.test8 fails on Apache Harmony. Fixes 49003.
? TestLogMF.testDebugDate fails on gcj. Fixes 49004.
? TelnetAppenderTest.testIt fails on gcj. Fixes 49005.
? Eclipse Java Compiler and gcj do not support -source=1.2. Fixes 49006.
? CachedDateFormatTest fails on Apache Harmony. Fixes 49007.
? Add %p{-2} pattern to EnhancedPatternLayout to drop two leading elements from name. Fixes 49010.
? Add %throwable{n} and {-n} pattern to EnhancedPatternLayout to print n or drop last n lines. Fixes 48902.

Release 1.2.15 - 2007-08-24

Type Changes By
? log4j 1.2.15 release preparation. Fixes 40951.
? Switch to NOPLoggerRepository if application reloading nulls repositorySelector. Fixes 40212.
? Add 'application' property support to SocketAppender (from 1.3) Fixes 43202.
? Log4JEntityResolver will return null if log4j.dtd can not be found on classpath. Fixes 43200.
? HierarchyEventListener.removeAppenderEvent never called. Fixes 37736.
? XMLLayout does not escape CDATA sections within NDC or throwables. Fixes 37560.
? Added test to confirm that DOMConfigurator.configureAndWatch does configure. Fixes 33502.
? Default initialization with XML file halts program if JAXP not available. Fixes 32527.
? Add reset option to PropertyConfigurator and DOMConfigurator. Fixes 17531.
? Error message always logged to LogLog when calling close on TelnetAppender. Fixes 14350.
? Add configurable triggeringPolicy for SMTPAppender. Fixes 32572.
? NullPointerException in MDC on Tomcat reload. Fixes 43181.
? Notice to use UTF-8 or UTF-16 encoding added to XML and HTMLLayout javadoc. Fixes 34874.
? XML and HTMLLayout do not always escape special characters. Fixes 34875.
? Optionally render MDC content in XMLLayout Fixes 43078.
? Typo in log4j.dtd concerning threshold. Fixes 42694.
? ERFATestCase fails on some JDK's. Fixes 42611.
? SocketNode can leak Sockets. Fixes 42585.
? Migrate to Maven based build and documentation. Fixes 37930.
? Prepare Maven release bundles. Fixes 40604.
? Eclipse compiler warning cleanup. Fixes 42283.
? JRockit VM and java-gcj fail unit tests. Fixes 42281.
? SocketAppender does not use FallbackErrorHandler Fixes 21796.
? Enhance DOMConfigurator to delegate unrecognized elements to configured object. Fixes 42257.
? Add LoggingEvent accessors. Fixes 42108.
? InstanceAlreadyExistsException using MBean. Fixes 42017.
? Reduce first connection failure severity in SocketAppender Fixes 29227.
? SyslogAppender does not limit packets to 1024 bytes. Fixes 42087.
? SyslogAppender: Added "header" property which if set to true will cause the appender to produce the HEADER part (timestamp and hostname) of the syslog packet. Default value is false for compatibility with previous behavior. Fixes 41040.
? SyslogAppender also now sends any header from the associated layout when activateOptions is called or first logging event is sent and any footer when the appender is closed. Fixes 40161.
? SyslogAppender leaks descriptors Fixes 37282.
? SyslogAppender assumes all lines start with tab Fixes 40502.
? SyslogAppender does not limit packet size to 1024 bytes Fixes 42087.
? NTEventLogAppender: Updated NTEventLogAppender.dll which corrects missing event messages and which should work with earlier releases of log4j. NTEventLogAppender.dll also now supports registration and unregistration using regsvr32. If replacing an existing copy of NTEventLogAppender, use "regsvr32 NTDllEventLogAppender.dll" or manually remove the HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/Eventlog/Application/Log4J registry key. Fixes 41169.
? NTEventLogAppender.dll performs unnecessary code page conversion using code copied from book. Fixes 39437.
? PropertyConfigurator.configure(URL) does not close resource stream. Fixes 40944.
? In Turkish locale level "info" is not equivalent to "INFO" Fixes 40937.
? Javadoc of PatternLayout should use %n in TTCC layout examples Fixes 41339.
? Stacktraces of exceptions disappear occassionally Fixes 41219.
? Incorrect message when specified custom level class does not implement toLevel Fixes 38680.
? Warning when configuring inner-class logger Fixes 41487.
? AsyncAppender in 1.2.14 DiscardSummary events create NullPointerExceptions in layouts Fixes 41186.
? Add target to generate binary and source compatibility report Fixes 37864.
? PropertyPrinter.printOptions breaking signature change in log4j 1.2.9 Fixes 41708.
? RollingFileAppender may delete files during rollover Fixes 41735.
? XMLConfiguration of loggerFactory does not work Fixes 33708.
? SyslogAppender does not limit packet size to 1024 bytes Fixes 42087.
? Update source per new ASF Header Policy. Fixes 40755.
? DateLayoutTest fails if default Locale is not en_US. Fixes 41373.
? Stacktrace may choke on null fields. Fixes 35324.
? Add projects.apache.org project descriptor. Fixes 41575.

Release 1.2.14 - 2006-09-18

Type Changes By
? Monitor deadlock in AsyncAppender. Fixes 38137.
? AsyncAppender: Dispatcher should run at normal prio. Fixes 28006.
? AsyncAppender wait forever when buffer is full. Fixes 37904.
? Add non-blocking option for AsyncAppender. Fixes 38982.
? Add SyslogPort option to SyslogAppender. Fixes 39687.
? Add cc and bcc addresses to SMTPAppender. Fixes 19125.
? Add password authentication to SMTPAppender. Fixes 24969.
? NullPointerException in org.apache.log4j.NDC.get. Fixes 40159.
? org.apache.log4j.lf5.util.DateFormatManager.setTimeZone assignment error. Fixes 36787.
? Monthly logs not generated at midnight with DailyRollingFileAppender. Fixes 38559.
? PatternLayout specifier %r is not consistent with documentation. Fixes 40145.
? Space after log level causes default level to be used. Fixes 37119.
? Bad patterns in ISO8601DateFormat and DateTimeDateFormat. Fixes 39135.
? SyslogAppender throws NullPointerException upon misconfiguration. Fixes 35743.
? FallbackErrorHandler throws NullPointerException if no loggers are set. Fixes 15501.
? Bad documentation for WriterAppender.encoding. Fixes 38564.
? NTEventLogAppender not build, tested and placed in distribution. Fixes 37866.
? SMTPAppender does not output newlines between stack trace lines. Fixes 38662.
? SMTPAppender will not run within sandbox. Fixes 30294.
? MDC with SMTPAppender doesn't work. Fixes 16922.
? Misspelling in HierarchyDynamicMBean. Fixes 31507.
? Additivity not exported by PropertyPrinter. Fixes 35123.
? RollingFileAppender, if removed, can cause NullPointerExceptions. Fixes 31003.
? AsyncAppender blocks on thread death. Fixes 23021.
? NOTICE file added to distribution and jars. Fixes 40412.
? Chainsaw of log4j 1.2 does not show TRACE level. Fixes 40378.
? TRACE level missing in short introduction to log4j. Fixes 40501.
? Update site generation to velocity 1.4 and remove dependency on logging/site project. Fixes 37960.

Release 1.2.13 - 2005-12-04

Type Changes By
? Location info missing for TRACE level messages. Fixes 36800.
? Console appender now behaves as before to fix compatibility problem with JBoss introduced in 1.2.12 release due to fix for bug 31056. Can still be configured to detect changes in the System.out and System.err streams as needed by setting the follow property. Fixes 37122.

Release 1.2.12 - 2005-08-29

Type Changes By
? Removed final qualifiers on member variables in org.apache.log4j.chainsaw.LoggingReceiver which would cause spurious compiler errors with JDK 1.1 and 1.2 javac compilers. Fixes 36262.
? Added a jndi.jar property to the build.xml. Fixes 36267.
? Added "release" target to build.xml. Fixes 37268.
? Removed references to obsolete documentation. Fixes 36213.
? Added protected accessors for member variables topicConnection, topicSession, and topicPublisher. Fixes 35965.
? SyslogAppender now checks Layout.ignoresThrowable() just like every other appender. Fixes 34026.
? DOMConfigurator would call LogLog.error to report XML validation errors that caused no problems in the interpretation of the configuration file. Fixes 35947.
? Fixed the JavaDoc links for the XML sample files. Fixes 14551.
? Added getNext/setNext methods to org.apache.log4j.spi.Filter and deprecated public "next" field. This mirrors the same change in the upcoming 1.3 version and, hence, provides a migration path. Fixes 35654.
? Added o.a.log4j.Logger.trace(), o.a.log4j.Logger.isTraceEnabled() and o.a.log4j.Level.TRACE Fixes 35711.
? Implemented serialization for Level. Fixes 34758.
? o.a.log4j.ConsoleAppender would ignore redirections of System.out and System.err that occurred after configuration. Fixes 31056.
? o.a.log4j.xml.DOMConfigurator would not properly interpret relative path names in external entity declarations. Fixes 23705.
? o.a.log4j.xml.XmlLayout would not properly escape class names that contained '<' or '>'. Fixes 35691.
? Use of String.intern() in o.a.log4j.CategoryKey would cause application to slow down. Fixes 35052.
? o.a.log4j.FileAppender would not create log file if parent directory did not exist. Fixes 9150.
? o.a.log4j.AsyncAppender would deadlock if a unchecked exception occurred in the attached appender causing the dispatch thread to die. Fixes 23021.
? Added jdiff target to build.xml. Fixes 35516.
? log4j would not build with a JDK 1.5 javac. Fixes 35831.
? Added log4j 1.1 compatibility method to o.a.l.helpers.Loader. Fixes 35893.
? Additional null terminating character in Windows nteventlog.cpp code. Fixes 34981.
? Broken links to J2SE classes in javadocs. Fixes 36332.

Release 1.2.11 - 2005-06-18

Type Changes By
? o.a.log4j.or.jms.MessageRenderer would not be compiled in the build.jms target. Fixes 34491.

Release 1.2.10 - 2005-04-28

Type Changes By
? Version 1.2.10 was not released following the accepted rules and process of the log4j project and Logging Services Project and was recalled and removed. Please do not use version 1.2.10, it is not an official log4j release.

Release 1.2.9 - 2004-11-01

Type Changes By
? Log4j version 1.2.9, is identical to version 1.2.8, except that several key methods have been deprecated in preparation for version 1.3.0, the next major release of log4j. These changes are intended to enforce the rule that client code should never refer to the Category class directly, but use the Logger class instead. Similarly, client code should not refer to the Priority class but to the Level class instead. For a more detailed discussion, refer to the document entitled preparing for log4j 1.3 at: http://www.qos.ch/logging/preparingFor13.jsp

Release 1.2.8 - 2003-02-19

Type Changes By
? XMLAppender would throw a NullPointerException if the input message was null. Many thanks to David Vandegrift for reporting the bug and to Hendrik Brummermann for supplying the patch. Fixes 11570.
? Various versions of Xerces would not parse log4j configuration scripts expressed in XML format. Fixes 12366.
? The "removes" buffer used in the flushBuffer() method of JDBCAppender is now cleared, solving the memory leak. Thanks to John Landers for reporting the bug and suggesting the fix. Fixes 14827.
? SocketAppender now honors ReconnectionDelay of 0. Many thanks to Scott Schram for reporting the bug and providing the fix. Fixes 15599.

Release 1.2.7 - 2002-10-09

Type Changes By
? Log4j now searches for the file log4j.xml as well as the file log4j.properties during log4j initialization.

Release 1.2.6 - 2002-07-31

Type Changes By
? Add of new options in JMSAppender and new command line arguments in JMSSink.
? Add new method getLoggerName() in LoggingEvent class. The getLoggerName is the preferred way for accessing the logger name. The public access categoryName field should not be accessed directly. Similarly, added the getLevel method which is now the preferred way of accessing the event's level. The public access level field should not be accessed directly. The javadocs now mark the categoryName and level fields as deprecated. Modified existing appenders to comply with these new directives.
? Log4j now will check if a system property named "log4j.ignoreTCL" is set. If it is set, then it will ignore the Thread Context ClassLoader when loading classes. This solves the irritating "appender is not assignable to Appender" messages observed when log4j.jar is loaded by multiple class loaders. The error reporting for this problem was also improved.
? Calling the MDC.get method with a null argument would throw a NullPointerException. Fixes 10528.

Release 1.2.5 - 2002-07-05

Type Changes By
? Calling an AsyncAppender close method also closes the embedded appender instances. Fixes 10185.

Release 1.2.4 - 2002-06-12

Type Changes By
? The JDBCAppender is marked as slated for replacement. Do not build critical software using it.
? Add LF5 documentation and examples. Further tests are required for full integration.
? XMLLayout can now output messages which contain embedded CDATA sections.Many thanks to Michael A. McAngus for supplying the relevant patch.
? The dispatcher thread associated with AsyncAppender is now marked as a deamon thread. Fixes 9750.
? Add missing NTEventLogAppender.dll Fixes 9606.
? log4j.dtd was changed so that <log4j:event> is now made of logger and level attributes instead of category and priority. Changed XMLLayout to conform to the DTD. Chainsaw was changed to adapt to the XMLLayout. Fixes 9435.
? Add missing LevelRangeFilter file.

Release 1.2.3 - 2002-05-24

Type Changes By
? SyslogAppender would incorrectly compute the length of the datagram to send to the remote syslogd host. Reported by Mamoru Kadota. Fixes 9285.
? The stack trace of exception would not be properly printed on the Compaq tru64 Unix platform. Initially reported by Fabrice Claes and later by Espen H. Kolstad who also provided the fix. Fixes 8505.

Release 1.2.2 - 2002-05-22

Type Changes By
? Log4j configurators take the "NULL" string value as a synonym for "INHERITED". Both of these two strings are legal level values for setting the level of a logger. Both values are case insensitive.
? When loading component classes, log4j will now first attempt to use the Thread Context Loader and if that fails, it will use Class.forName. In log4j 1.2 and 1.2.1, only Class.forName was used and the TCL was ignored. This change is a response to bug #9305 opened by Scott M. Stark. Fixes 9305.

Release 1.2.1 - 2002-05-17

Type Changes By
? LoggingEvent.getMDCCopy() method now sets mdcCopyLookupRequired instead of ndcLookupRequired. This bug would cause the wrong MDC information to appear on a log server. It could only occur if the client wrapped an AsyncAppender around a SocketAppender or if the server used an AsyncAppender for its logging. Fixes 9155.

Release 1.2 - 2002-05-01

Type Changes By
? A closed TelnetAppender would continue waiting for connections even if its ServerSocket was closed. This caused the TelnetSocket to sit in a loop and complain about the closed socket. Fixes 8527.
? AsyncAppender throws NullPointerException problem. The bug was actually in AppenderSkeleton. Fixes 5444.
? Add support for recursive variable substiuton as requested by Eric Chastan.
? SocketNode now used a BufferedInputStream as suggested by Kok Chong Fixes 3933.
? Fixed a problem with DailiyRollingAppender which would not correctly compute the rollover period in certain timezones. Fixes 7550.
? Fixed documentation bug #2726 in FAQ.html. Fixes 2726.
? Added a flush statement in the WriterAppender.writeFooter method. Fixes 2383.
? In XMLLayout, escaped the method attribute. The XMLLayout also outputs each item of a stack trace in a separate line.
? The LoggingEvent.getMDCCopy method now clones the MDC instead of just referencing it. Fixes 5932.
? The ANT build script was modified to use jar files specified in the build.properties file instead of the CLASSPATH environment variable. The build.properties file depends on local paths and is supplied by the user. The build.properties.sample file is included in the distribution. The build.sh and build.bat scripts have been removed. This is the way many other jakarta projects build their projects. The jar files in the dist/lib directory were also removed since they are no longer used.
? The DOMConfigurator now interprets the string after the '#' character in the value attribute within the <level> element as the fully qualified class name of a custom Level. This is consistent with the way log4j handles "level" values in other places. The class attribute is still honored.
? Add Oliver Burn's chainsaw tool to the core log4j distribution. Visualisation and dynamic filtering of log events is bound to be a very important area of activity in the future.
? Add the org.apache.log4j.jdbc.JDBCAppender which as the name indicates sends events to a database using the JDBC API. Thanks to Kevin Steppe for supplying the code.
? Add SocketHubAppender class as contributed by Mark Womack. This appender sends LoggingEvent objects to a set of remote a log servers.
? In the Category class, the getChainedPriority method has been replaced with getEffectiveLevel method.
? Replaced the custom class loading based on the thread context class loader with a simple Class.forName() call. This solves two allied but distinct problems encountered when using Ant with JUnit although the bug is more general. In one instance of the problem, log4j would throw java.lang.NoClassDefFoundError for org/apache/log4j/AppenderSkeleton where log4j.jar and related classes were clearly available to the Ant classloader. In another incarnation, log4j would reject a custom appender claiming that it is not assignable to a org.apache.log4j.Appender variable. This would occur when log4j.jar was available to both the Ant classloader and the system classloader. Thanks to Dave Herman for providing detailed scenarios exposing the issues involved. See http://forum.java.sun.com/thread.jsp?forum=38&thread=70946 http://forum.java.sun.com/thread.jsp?forum=38&thread=70946#479697 http://marc.theaimsgroup.com/?l=ant-user&m=101139178705895&w=2 for more details.
? Fixed the complaints the compiler issued when using the Logger.setLevel() method.
? Incorporated the performance enhancements to ISO8601DateFormat and AbsoluteTimeDateFormat classes submitted by Andrew Vajoczki.
? Source code written for log4j 1.1.3.jar will compile fine with log4j 1.2X. However, code compiled for log4j 1.1.3 would previously systematically throw "java.lang.NoSuchMethodError" runtime exceptions when run with log4j 1.2 - prior to beta2. This problem has been corrected in beta2. Pheew, that was a close one.
? Log4j 1.2 is now backward compatible in serialization of LoggingEvents. For example, a 1.1.3 SocketAppedner can write to 1.2 SocketServer. Similarly a 1.2 JMSAppender will work with 1.1.3 JMSSink. This should ease the move to log4j 1.2, especially in large deployments.
? The src/java/org/apache/log4j/examples/ directory moved under the top-level directory as examples/.
? Fixed the ArrayIndexOutOfBoundsException that was thrown by AsyncAppender if multiple threads were trying to log an event containing an exception near simultaneously. Thanks to Thomas Tuft Muller for reporting this bug.
? Improved error reporting in DOMConfigurator. Thanks to Thomas Tuft Muller for contributing the enhancement.
? Log4j is now configurable using JMX. JMX support is not of production quality.
? Add support for different encodings in WriterAppender. Thanks to Ben Sandee for submitting the relevant patch.
? Modified SMTPAppender to allow multiple email sessions. Thanks to Jon Skeet for supplying the relevant patch.
? The CategoryFactory class has been replaced by the LoggerFactory class. The makeNewCategoryInstance method has been renamed as makeNewLoggerInstance. This change requires subclasses of Category classes to be modified and recompiled.
? The Level class replaced the Priority class. Priority class now extends Level to preserve backward compatibility.
? The Logger class replaced the Category class. Logger class extends Category to preserve backward compatibility. We proudly mark this change with a single star for 100% compatibility.
? The Category.assert method has been replaced by Category.assertLog. This change was necessary because assert is a language reserved word in JDK 1.4.
? Removed deprecated methods setOptions and getOptionStrings defined in the org.apache.log4j.spi.OptionHandler interface. This interface is implemented by most log4j appenders and layouts. In particular, all appenders and layouts shipped with log4j contain these deprecated methods. They have become totally redundant after we moved to JavaBeans style configuration in log4j 1.1.
? The disable(Level) methods in Hierarchy have been removed and been replaced by threshold methods.
? Add buffered IO capability to FileAppender and subclasses.
? The location information (or stack information) was not correctly transmitted by JMSAppender.
? Add event reporting capability to the Hierarchy class.
? Add new system property "log4j.configuratorClass". This property allows the user to specify the custom configurator at the default initialization phase. This property replaces the previous interpretation of the reference part of "log4j.configuration" as the custom configurator class. This interpretation was sometimes erroneous and caused headaches.
? Introduced the Mapped Diagnostic Context or MDC class. This class is similar to the NDC except that the diagnostic context is based on a map instead of a stack. Moreover the MDC is automatically inherited by child threads under JDK 1.2 and above.
? Corrected a performance bug in the NDC class as observed by Dan Milstein and independently by Ray Millard.
? Removed deprecated methods disable(Priority), disableAll, disableDebug, disableInfo and enableAll in BasicConfigurator.
? Add supports java.io.Reader objects in the method doConfigure(), instead of only InputStream. Thanks to Mark Womack for submitting the relevant patch.
? Corrected the restart bug in DailyRollingFileAppender. Thanks to Jim Moore for supplying the relevant patch.

Release 1.1.3 - 2001-06-19

Type Changes By
? Add a missing namespace declaration in the log4j:configuration element in log4j.dtd. The missing declaration caused the new generation of namespace aware parsers to barf when parsing log4j configuration files.
? Reduced the size of log4j-core.jar to 78KB.
? Minor documentation changes.

Release 1.1.2 - 2001-06-07

Type Changes By
? Corrected a problem with the static initializer of the Category class which would use the wrong class loader to search for the default configuration file. The associated search algorithm has been also simplified. Nevertheless, the preferred method to specify the automatic configuration file is by setting the log4j.configuration system property.
? Documentation improvements. Added a new section to the manual explaining the default initialization procedure
? Enhancements to the org.apache.log4j.examples.appserver package.
? Corrected a bug in the way the NTEventLogAppender printed exceptions.

Release 1.1.1 - 2001-05-20

Type Changes By
? Add missing custom priority support in PropertyConfigurator.
? Made a number of fields protected instead of default access in SMTPAppender.

Release 1.1 - 2001-05-19

Type Changes By
? This release has the same code as 1.1b7. It differs only in a few minor documentation changes.

Release 1.1b7 - 2001-05-09

Type Changes By
? Made BasicConfigurator disable methods static as they were in log4j 1.0.4. Thanks to Francisco Marin for reporting the bug.
? Corrected a two related deadlock problems introduced while fixing bug 1505. Thanks to joelr@viair.com for reporting the problem. Fixes 1505.
? The configureAndWatch methods in Configurators did not close the configuration file, preventing its editing. Fixes 1686.
? In DOMConfigurator.setParameter special character conversion now precedes variable substitution. This change was suggested by Steven Velez. The vast majority of users should be oblivious to it.
? The TextPaneAppender is no longer maintained and has been removed. It is still available under the contribs/ directory. This change has been discussed in the log4j mailing lists and no one objected to the removal of the TextPaneAppender class.

Release 1.1b6 - 2001-04-26

Type Changes By
? Aaron Greenhouse from Carnegie Mellon SCS found a series of multi-threading related bugs in Category and AsyncAppender. See bug ids 1505 and 1507 in our bug database for exemplary bug reports. They are worth the detour. Fixes 1505.
? InvalidJarIndexException is only available in JDK 1.3. Referring to this exception type caused log4j 1.1b5 to break on earlier JDKs. We now avoid referring to it.
? Add PriorityRangeFilter by Simon Kitching. See the Threshold option in AppenderSkeleton for a more convenient alternative.

Release 1.1b5 - 2001-04-22

Type Changes By
? In HTMLLayout, the Title option sets the HTML document title (<title>...<title>).
? Corrected an important performance bug in LocationInfo. Hein Couwet and kr@it-practice.dk have independently identified the bug. This is yet another example of the difference made by the number of eyeballs studying source code.
? Corrected the incorrect value returned by LocationInfo.getClassName method when running under IBM Visual Age. Thanks to Mathias Rupprecht for supplying the relevant patch.
? Corrected a bug where the build.sh file in the distribution would be in DOS CRLF format. Thanks to ma.darche@free.fr for reporting the problem.
? Corrected InvalidJarIndexException thrown in applets while searching for the default log4j configuration file. Thanks to Michael Lundahl for reporting this bug.
? Add missing PropertySetterException class to log4j-core.jar. Thanks to ma.darche@free.fr for reporting this bug.

Release 1.1b4 - 2001-04-20

Type Changes By
? Mathias Bogaert observed that in version 1.1b3 the search algorithm for the resource used in automatic log4j configuration was different than in 1.0.x. Beta4 uses a more powerful mechanism which is also compatible with 1.0.x.
? Paul Glezen correctly observed that if log4j is deployed in a client/server mode where multiple log4j clients log to a log4j server, all hosts must be upgraded to version 1.1 in one go because the internal LoggingEvent class used in client/server communication changed in log4j 1.1.

Release 1.1b3 - 2001-04-18

Type Changes By
? Add a RollingFileAppenderBeanInfo class that fakes the maxFileSize JavaBeans property as a String type instead of a long. This allows us to resuscitate setMaxFileSize(long) method that was removed in 1.1b2 breaking 100% backward compatibility. This addition restores 100% backward compatibility.

Release 1.1b2 - 2001-04-18

Type Changes By
? The directory structure has changed to better suit Jakarta conventions
? Add a few jar files required at build time to build/lib so that it is now possible to compile log4j out of the box.
? Whenever a priority parameter is expected in a configuration file, one can now use a custom priority class. See OptionConverter.toPriority method for more information. Note that the <priority> element in log4j.dtd remains unaffected by this change.
? Add the setQuietMode(boolean) method to LogLog. In quiet mode LogLog will not output anything even in case of errors.
? Log4j components are now configured as JavaBeans. The setOption and getOptionString methods have been deprecated in OptionHandler interface which is implemented by most log4j components.
? The stack trace of a throwable passed in a logging statement is not parsed into a stack array which is serializable. This allows cascading of log4j servers to properly propagate throwable information.
? In XML configuration files, the <configuration> element has been deprecated and was replaced by the <log4j:configuration> element.
? The "log4j.configDebug" system property has been replaced with the "log4j.debug" system property although it is still available. Similarly, the "configDebug" attribute has been deprecated and replaced with the "debug" attribute in log4j.dtd.

Release 1.1b1 - 2001-02-23

Type Changes By
? Logging can now be disabled per Hierarchy. It can also be disabled using configuration files using the "disable" directive. The "disableOverride" directive takes precedence over the "disable" directive. As a result of this change the disable family of methods in BasicConfigurator has been deprecated and replaced by the same family of methods in the Hierarchy class.
? The FileAppender has been split into three parts: WriterAppender, ConsoleAppender and FileAppender. ConsoleAppender takes over the console logging functionality of FileAppender. As a result support for stream and console printing has been deprecated in FileAppender.
? The FileAppender now correctly outputs the header and footer of its layout. This problem was reported by too many users to list here.
? Appenders and Layouts now get to see the raw message object in LoggingEvent not just its rendered form. The access modifiers of some LoggingEvent fields were changed so that they can be accessed in less error-prone ways. Thanks to Jim Cakalic and Anders Kristens for their valuable advice.
? Add getLayout(), getErrorHandler(), and getFilter() to the Appender interface.
? Add getOption(key) method to the OptionHandler interface and modified implementations of it as appropriate.
? Add the much awaited DailyRollingFileAppender.
? The structure of the distribution changed somewhat. The log4j.jar files can be found under dist/. The javadoc directory has been moved to docs/api/. We are now totally dependent on ANT to perform all the steps involved in creating a release, including compilation, jar file creation, generation of the javadocs, and for the creation of the distribution tar and zip files.
? Removed org/apache/log4j/varia/ResilientFileAppender.java which was bogus to begin with.
? XMLLayout will now mark some output as <![CDATA[ .. ]]> so that it does not get interpreted by the XML parser. This was suggested by Mathias Bogaert like a long list of other fixes.
? Corrected a bug in CyclicBuffer.resize method that would not update the next insertion point. Thanks to Ole Bulbuk for accurately reporting the bug.
? The LoggingEvent class now supports serialization of priorities derived from the org.apache.log4j.Priority class.
? Improved the search method for finding the "log4j.properties" file in the static initializer of Category class. Thanks to Calvin Chan for supplying a better method.
? The code handling the FCQN (formerly instanceFQN) parameter was cleaned up. There is now a well-established and simple manner for sub-classes of Category (or wrapper classes) to define the FCQN variable: just define a static variable, say FCQN, consisting of the fully qualified class name of the subclass or wrapper, supply this variable as an argument to forcedLog method if and when the sub-class or wrapper invokes that method.
? Made the instanceFCQN an instance variable instead of a class static in Category.java. In related move, the Category constructor now takes an additional argument setting the instanceFCQN. This makes life less miserable for Category subclasses.
? Corrected a bug in the OptionConverter.instantiateByClassName method that would not return the defaultValue in case of error. Thanks to Matthieu Verbert for identifying this bug.
? Corrected the missing stack trace in e-mails generated by the SMTPAppender when using certain Layouts.
? Updated the "Adding Conversion Characters to PatternLayout" document to reflect the latest changes to the code. Also added the org/apache/log4j/examples/appserver directory containing the associated example code.
? Add the BufferSize option to the AsyncAppender.
? Eliminated the SecurityExceptions thrown in Applets. Thanks Timur Zambalayev for reporting this bug.
? Fixed the erroneously thrown IOInterruptedException when the AsyncAppender was closed. Thanks to Tom Palmer for accurately reporting this bug.

Release 1.0.4 - 2001-01-12

Type Changes By
? Corrected a serious bug in Hierarchy.java that would cause a NullPointerException depending on the order of instantiation of categories. Thanks to Wolfram Gewohn for reporting this bug.
? Corrected a bug in the getOptionsStrings method of SMTPAppender that omitted to mention the EvaluatorClass option. Thanks to Mark Balster for reporting this bug.

Release 1.0.3 - 2001-01-11

Type Changes By
? Fixed a NullPointerException occurring in AsyncAppender after invoking Category.shutdown. Thanks to Frank-Olaf Lohmann for reporting this bug.
? Modified the OptionConverter.selectAndConfigure method to take an extra argument of type Hierarchy. This method is used internally and should not affect most users.
? Add the warn method to LogLog which is used internally by log4j to report on itself.
? Displaced a number of HTML files under the docs directory. The new structure is compatible with the jakarta site and results in a more consistent navigation experience.
? Made a few improvements in the javadocs.

Release 1.0.2 - 2001-01-11

Type Changes By
? Add the missing build.inc file to the distribution. No code changed.

Release 1.0.1 - 2001-01-10

Type Changes By
? This version corrects some documentation and build script bugs; code has not changed.

Release 1.0 - 2001-01-08

Type Changes By
? Package hierarchy now starts at org.apache.log4j.
? Add the fatal() family of methods to the Category class. Moreover, the EMERG priority has been removed from the Priority class. This priority has been replaced by the FATAL priority that is more widely accepted. This change will require EMERG log statements to be replaced by FATAL log statements. Assuming EMERG log statements are rare, this should have a small but bearable impact on existing client code. Moreover, the Unix Syslog priorities ALERT, CRIT and NOTICE are no longer recognized. Support for these priorities was minimal and few users should suffer from these changes.
? Removed the methods setRootPriority, getRootPriority as these methods were redundant and had been previously deprecated.
? Removed the DOM Level 2 dependency in DOMConfigurator. This makes log4j XML configurable using Sun's parser or Apache's Xerces.
? The static initializer of the Category class now takes the log4j.configuration system property to search for its configuration file. The type of the configurator used to parse the configuration file depends on the value of the log4j.configuration system property.
? Enhanced the PropertyConfigurator and DOMConfigurator to support customisation of independent Hierarchy instances. The org.apache.log4j.net.SocketServer has been enhanced to take advantage of this functionality. The old code of SocketServer has been moved to SimpleSocketServer.
? Enhanced the PropertyConfigurator to support variable substitution for all options *values* (but not keys!).
? Categories are now aware of the Hierarchy they are linked to. This will provide a basis for several performance enhancements planned for the future.
? Add support for object rendering. It is now possible to register an object renderer for a given object type. When the given object needs to be logged log4j will invoke the corresponding renderer to transform the object into a String. As a result of this enhancement, all the String forms of all the printing methods such as debug(String), info(String) have been removed as they are no longer necessary. This change should be backward compatible but requires recompilation of old client code. Thanks to Michael Smith for noting the recompilation requirement.
? Add support for user defined category factories in the PropertyConfigurator. Thus, it is now possible to configure log4j with a properties file and still use custom Category sub-classes. The DOMConfigurator had already a finer grain support.
? Add the SMTPAppender that in case of an error or fatal event sends an e-mail containing latest N logging events in its buffer, where N is chosen by the user.
? Add the method getInstance(Class) to the Category class.
? Corrected a bug in configureAndWatch method of configurators that would configure log4j only after an unnecessary delay.

Release 0.9.1 - 2000-11-30

Type Changes By
? Corrected a typo making NTEventLogAppender.dll register the wrong category message file. Thanks to Peter Hayes for accurately reporting this bug.
? The DOMConfigurator and PropertyConfigurator can now automatically detect modified configuration files and re-read them.
? Add AsyncAppender which buffers log requests and serves them at a later time. AsyncAppender can increase logging performance tremendously if logging operations are interspersed with long and blocking non CPU-intensive operations, typically I/O or network access. For CPU intensive applications, using the AsyncAppender will actualy degrade logging performance by 10 to 25 percent.
? The log4j.dtd has been modified to allow appenders to refer to other appenders by IDREF.
? The DOMConfigurator has been modified to take advantage of ID/IDREF attributes when referring to appenders. This change requires a DOM Level-2 API compliant parser. DOM Level-2 java bindings are available at http://www.w3.org/TR/1999/WD-DOM-Level-2-19990923/java-binding.html.
? Add the configure(String filename) method to DOMConfigurator. This method requires the presence of a JAXP compatible parser. At this time, the only DOM2 and JAXP compatible parser seems to be the Apache xerces parser.
? Add the PriorityMatchFilter allowing filtering by exact priority match. This was a common request by users.
? The configuration of a category is now an atomic operation. This ensures that log requests are not lost while configuration is in progress. Anders Kristensen was to first to observe the potential problems in non-atomic configurations.

Release 0.9.0 - 2000-11-20

Type Changes By
? The "log4j" element has been renamed to "configuration" in the log4j DTD. This change requires that log4j configuration files written in XML be modified. Since the log4j element figures only once in the XML file, this change should take little time.
? ResourceBundles are now category instance specific and no longer class static. Moreover, like other properties resource bundles are inherited from the category hierarchy.
? The jar files log4j.jar and log4j-full.jar now contain versioning information in their respective manifest files.
? Corrected an inconsistency in the NTEventLogAppender which broke it.
? Fixed a bug where configuration files were not parsed correctely due to trailing spaces in option values as returned by java.util.Properties. Trailing spaces are now removed from option values. This bug was quite disconcerting because the trailing spaces cannot be seen without careful examination of the configuration file.
? Add the XMLLayout. The output of the XMLLayout consists of a series of log4j:event elements. It does not output a complete XML file. The output is designed to be included as an external entity to form a well-formed XML file.
? Add a new abstract class org.log4j.helpers.DateLayout. The TTCCLayout now extends DateLayout.
? Corrected a rather subtle performance bug in the buffer management code in PatternLayout. Thanks to Vladislav Dutov and Constantine A. Plotnikov for for insisting on the correction of this bug.
? Created a new package called org.log4j.spi. This new package holds classes that are hidden from the casual user but are needed to extend log4j.
? Add org.log4j.varia.ExternallyRolledFileAppender to handle externally triggered file rollovers.
? Add support for multiple hierarchy trees.
? PatternLayout can now be subclassed to support new conversion patterns.
? Extended the DOMConfigurator and the log4j DTD to properly handle sub-classing of Category and Priority classes. There have been also minor adjustments to other classes to handle sub-classing. These changes should be invisible to users. All categories except the root category can be sub-classed and also assigned priorities sub-classing org.log4j.Priority. The root category always exists and CANNOT be subclassed. The ProppertyConfigurator remains unchanged. Thus, it does not handle extensions of the Category class.
? Add filter support in appenders. The DOMConfigurator and the log4j.dtd have been enhanced to support filters.
? Add error handling support to appenders. The DOMConfigurator and the log4j.dtd have been enhanced to support filters.
? Add support for correct interpretation of location information in IBM's Visual Age environment. Thanks to Wolf Siberski for supplying the relevant patch.
? Add getAdditivity method to Category. This feature was requested by Constantin Mitran. (mitran at ecircle.de)

Release 0.8.5b - 2000-08-27

Type Changes By
? Corrected multiple bugs in default initialization code of Category class. Thanks to Jeff Turner for identifying and supplying corrective patches.

Release 0.8.5a - 2000-08-24

Type Changes By
? Add the %n conversion character to PatternLayout so that a line separator can be specified in a platform independent way.
? In 0.8.5 internal Priority integer values were decoupled from the Unix Syslog values. This broke SyslogAppedder. A new function Priority.toSyslogInt is introduced to solve this bug.
? Corrected a bug where the internal priority integer

Release 0.8.5. - 2000-08-23

Type Changes By
? All log4j internal output is now prepended with the string "log4j: ". This makes is easier to differentiate log4j internal logs from messages output by other sources.
? Sub-classes of Category class must now specify their fully qualified name when constructing logging events. This allows the %C conversion specifier in PatternLayout to work properly even with sub-classes or wrappers of Category.
? Add the method disableDebug to BasicConfigurator. This method disables all print requests of debug priority regardless its category. Similar methods disableInfo, disable, disableAll and enableAll have also been added. Disable type methods can be overriden by setting the log4j.disableOverride system property. Calling BasicConfigurator.disableInfo is equivalent to the now deprecated flagAsShippedCode method.
? Given the above changes, the system property log4j.shippedCodeFlagOverride is no longer honored.
? It is now possible to sub-class Category. The sub-classes may continue to adhere to the category hierarchy. This was a frequently requested feature.
? Corrected a problem with the additivity flag being ignored in categories without appenders. This bug was discovered by Anders Kristensen.
? Add a method BasicConfigurator.resetConfiguration to reset the log4j environment. This method should be used sparingly.
? At the initialization of the Category class, the file log4j.properties will now be searched from the search path used to load classes. If the file can be found, then it is fed to the PropertyConfigurator.configure(java.net.URL) method.
? Failing to access system properties within the static initializer of BasicConfigurator class is no longer reported as an error but as a debug message. Thanks to Gilles Schlienger for reporting this problem with applets.
? Corrected a bug which caused infinite loops when using conversion patterns with a single element, fortunately under very rare circumstances. This bug was first reported by Igor Potraev, the author of log4p. It was independently reported by Joe Haberl from IBM Global Services.
? Add a mechanism to lazily remove references to dead threads in the NDC class. Indeed, in previous versions calling NDC.pop within a thread but forgetting to call to NDC.remove before exiting (that thread) resulted in a memory leak.
? Corrected a huge memory leak in SocketAppender. This leak was due to the ObjectOutputStream indefinitely holding a reference for each written to the stream. Thanks to Dan MacDonald for very accurately describing this bug.
? The log and l7dlog methods in Category no longer ignore the shipped code flag. This bug was reported by Mario Schomburg.
? Add missing NDC information to LoggingEvent.writeObject method.
? Corrected handling of SocketException in SocketNode. Thanks to Gerald Gutierez (ggutierez@emobiledata.com) for reporting this and the previous problem.
? Phased out custom shell scripts to build java documentation and jar files in favor of Jakarta's ANT. It was becoming a nuisance to keep the ANT build file in sync with the custom shell scripts.

Release 0.8.4d - 2000-05-11

Type Changes By
? The NT EventViewer no longer complains about missing message 4096.
? Minor corrections in documentation.
? Add missing icons GIFs into the distribution.
? SocketNode now attempts to close the socket when exiting. Thanks to Moses Hohman (mmhohman@rainbow.uchicago.edu) for noting this.
? Removed the com.ibm.log4j from the javadoc directory. This seems to confuse VAJ. Thanks to Steve Ashcroft for reporting this problem.

Release 0.8.4c - 2000-05-05

Type Changes By
? As a result of the infinite loop problem (see next item), added over 800 new test cases to stress-test the code in CategoryFactory class where category creation occurs.
? Under certain rare circumstances the Category.getInstance method entered an infinite loop. Thanks to Mario Schomburg from IBM Global Services / Hannover for identifying this problem and proposing a patch.
? DOMConfigurator and the log4j.dtd were out of sync on the type of the priority directive. As a result, priority directives all defaulted to DEBUG. Thanks to Peter (petervt@users.sourceforge.net) for accurately reporting this bug.
? Minor additions to the FAQ.
? Add the NumberCruncher example showing how the NDC class can be used to distinguish output from different clients.
? Add the %x conversion specifier to the TTCC_CONVERSION_PATTERN in the PatternLayout class. This is consistent expected output of Trivial.java example. Thanks to Jerome (schrom@users.sourceforge.net) for reporting this bug.

Release 0.8.4b - 2000-05-03

Type Changes By
? The value of the additivity option would not be parsed properly by the ProperytConfigurator if the line containing the option contained trailing spaces.

Release 0.8.4a - 2000-05-03

Type Changes By
? The localized logging methods (l7dlog) omitted priority based evaluation and erroneously logged all requests.

Release 0.8.4 - 2000-05-01

Type Changes By
? The close method was added to the Appender interface allowing appender implementations to release any resources they may have allocated.
? The package naming scheme of changed from "com.ibm.log4j.*" to "org.log4j.*". The new naming reflects the open source nature of the project and is consistent with the URL http://www.log4j.org.
? Add internationalization support. See the newly introduced l7dlog methods in Category class.
? In the FileAppender, the File option now admits variable substitution. For example, if "java.home" system property is set to /home/xyz and the File option is given the value "%{java.home}/test.log", then File option will be interpreted as "/home/xyz/test.log". Thanks to Avy Sharell (sharell@online.fr) for contributing this feature.
? SocketAppender is now officially part of the package. It is capable of sending logging events to a remote SocketNode. The SocketNode logs events according to server (local) policy. For example, a client can log events to a local file and also send them to a remote server (a SocketNode). This server can log the event to any number of files, to the console, to any number of TextPaneAppenders and even re-transmit the event to another server, and so forth. This paradigm is common in most logging systems, e.g. Syslog and NT Event Log. Many thanks to Andrew Harrison for showing a way to actually implement the paradigm.
? The Category.callAppenders method now accepts a LoggingEvent instead of creating one itself. This was necessary to accommodate events generated at a remote client.
? LoggingEvent class changed slightly to support remote logging. The category field (a Category) has been replaced by the categoryName field (a String).

Release 0.8.3b - 2000-04-14

Type Changes By
? Corrected a bug in Category.removeAppender(String) which would never remove the desired appender. Thanks to Moses Hohman for reporting this bug.

Release 0.8.3a - 2000-04-14

Type Changes By
? Corrected a bug RollingFileAppender which would throw an uncaught exception in case output file could not be opened for writing. Thanks to Vinay Aggarwal for signaling this problem.

Release 0.8.3 - 2000-04-13

Type Changes By
? The log4j.override key defined in BasicConfigurator has been renamed to log4j.shippedCodeFlagOverride.
? The getCurrentCategories method in the Category class would not return the correct value. Thanks to Timothy Potter (tpotter@agency.com) for reporting this problem.
? Appenders now admit a priority threshold as an option. All requests with a priority lower than the appender's threshold priority are ignored by the appender.
? Integrated Christopher Taylor's DOMConfigurator parsing XML configuration files.
? The jar file log4j-net.jar has been replaced by log4j-full.jar. It contains DOMConfigurator.class in addition to the com.ibm.log4j.net package.
? Add support for the ANT build tool. Thanks to Christopher Taylor for supplying the build.xml file. ANT is available form http://jakarta.apache.org.
? FileAppender's File option now accepts the values "System.out" or "System.err". If one these values is suppiled in a configuration file then the output is directed to the corresponding stream. Moreover, the default constructor of FileAppender no longer sets System.out as an output target nor does it define a default layout.
? Add caller class (C), caller file name (F), caller line number (L), caller method name (M) conversion specifiers to the PatternLayout class. The category conversion specifier now takes an optional precision modifier allowing the user to control the number of right most components in the category name that will be printed. Corrected a bug occuring when the caller file name and line number information were unavilable due to JIT compilation. In that case, the PatternLayout would not properly use the rest of the available location information. The above enhancements and bug-fixes originate from comments by Nelson Minar (nelson@monkey.org).

Release 0.8.2 - 2000-03-23

Type Changes By
? The SimpleLayout and TTCCLayout are replaced by the PatternLayout in the log4j.jar file to keep its size small. These two layouts are still part of the package.
? The PatternLayout class is introduced. This new layout is configurable using a conversion pattern which is parsed at runtime. This allows the user to choose the output layout without writing any code and only at a marginal performance cost compared to the dedicated layouts such as SimpleLayout and TTCCLayout. The PatternLayout also allows the user to determine minimum and maximum field lengths. The PatternLayout was written by Jim Cakalic (jim_cakalic@na.biomerieux.com).
? All internal components now use LoggingEvent instances to specifiy logging information.
? Corrected a problem with a missing variable initialization in SyslogAppender. This caused NullPinterException to be thrown when logging exceptions. Added a default constructor to SyslogAppender. The lack of this constructor caused PropertyConfigurator to throw a java.lang.InstantiationException when the appender type was set to be SyslogAppender. Thanks to Yves Bossel (ybossel@opengets.cl) for accurately identifying these bugs. Modified some other related option handling code in SyslogAppender.
? Made NDC.get public access instead of default access. Thanks to Y. J. Chun (monac@softonnet.com) for reporting this problem.
? PropertyConfigurator now parses the additivity option for categories.
? Corrected the value of the ADDITIVITY_PREFIX constant to match the documented value, that is "log4j.additivity".
? Corrected a really bad bug where System.out would be closed when PropertyConfigurator.configure was called. Thanks to Christopher Taylor (cstaylor@pacbell.net) for tracking and reporting this bug.
? The PropertyConfiguator now prints debug messages if the flag "log4j.configDebug" is defined in the configuration file. Previously, only if the system property "log4j.configDebug" was set would debug messages be printed. A question by Shawn Kircher (skircher@vninet.com) induced this change.
? In AbsoluteTimeDateFormat, DateTimeDateFormat and ISO8601DateFormat the separator between the seconds and milliseconds has been changed to comma from full stop, in order to be compliant with ISO8601's preferred sign. Thanks to Jim Cakalic (jim_cakalic@na.biomerieux.com) for pointing out this discrepancy with the standard.
? Corrected a bug where RollingFileAppender would not work properly on Windows systems. Thanks to Heinz Richter (heinz.richter@ecmwf.int) for noting this problem.

Release 0.8.1 - 2000-02-19

Type Changes By
? Core classes are now independent of the format of the options file. Configurable core classes implement the OptionHandler interface. OptionHandlers allows configurators to learn the relevant option names. The configurator feeds option values to the OptionHandler which configures itself. As a result of these changes, the Init class has been broken down to two separate classes: the BasicConfigurator and the PropertiesConfigurator. An XML configurator for 0.8.0 has been already written by Christopher Taylor (cstaylor@pacbell.net).
? Add multiple appender support per category. The appenders follow the category hierarchy, i.e. a child category inherits the appenders of its parents.
? Add an assert() method to the Category class. Steven Marcus (srnm@awaretechnologies.com) requested this addition.
? Automatic stack printing is no longer supported. This was an unused and unreliable feature which unnecessarily complicated the code.
? log4j now emits a single warning message when no appender to write to could be found. This is typically the case when the user forgets to configure the log4j environment. This change was suggested by Jim Cakalic (jim_cakalic@na.biomerieux.com).
? RollingFileAppender adds file roll over capability-implemented by Heinz Richter (heinz.richter@ecmwf.int).
? Corrected a bug where a java.lang.NoClassDefFoundError would be thrown because com.ibm.log4j.helpers.SyslogTracerPrintWriter was not included in log4j.jar. Thanks to Jim Cakalic (jim_cakalic@na.biomerieux.com) for signaling this bug.

Release 0.8.0 - 2000-02-09

Type Changes By
? There has been an important API changes. The Log, NOPLog and ILog classes have been removed. Their functionality has been migrated to the Category class. In this release, instead of writing ILog.debug(CAT, "Some message."); one will write CAT.debug("Some message."); Arndt Schoenewald <arndt@ibm23093i821.mc.schoenewald.de> observed that one could use the Category objects directly for logging.
? It is no longer possible to instantiate Category objects directly. Instead, one would use the factory method Category.getInstance(String name). [***] There category instantiation code was moved to CateogryFactory class. This class has package visibility and remains hidden from the user. This stylistic improvement was suggested by Luke Blanshard (luke@quiq.com).
? The Init class offers methods to initialize the log4j environment. The Init.flagAsShippedCode method replaces the NOPLog class.
? Changes in the documentation to reflect the API changes.
? The NDC.cloneStack and inherit methods now tolerate null-stacks.

Release 0.7.5 - 2000-01-29

Type Changes By
? TTCCLayout now takes a java.text.DateFormat object as a parameter. The task of formatting the date is delegated to this object. Added four classes extending the java.text.DateFormat class. These are RelativeTimeDateFormat, AbsoluteTimeDateFormat, DateTimeDateFormat and ISO8601DateFormat classes. Thanks to Arndt Schoenewald <arndt@ibm23093i821.mc.schoenewald.de> for suggesting the ISO8601 date format. These four classes can be parametrized with a particular TimeZone. The TTCCLayout class now accepts a new configuration file option called "TimeZone". These four DateFormats are less malleable than the java.text.SimpleDateFormat but they are also much faster. As a consequence of these changes, the setRelativeTime, setDatePrinting methods in TTCCLayout have been removed along with the associated configuration file options RelativeTime, DatePrinting and TimePrinting. The current code is inspired by code contributed by Heinz Richter (heinz.richter@ecmwf.int).
? The Log.emerg method has been deprecated. If you use statements of EMERG priority, please use the Log.log form instead.
? Add getDepth and setMaxdepth methods to the NDC class. This makes it easier to manage the nested context depth especially when callees push but forget to pop.
? Moved the documentation in com/ibm/log4j/package.html to com/ibm/log4j/overview.html. Many users were failing to read the com/ibm/log4j/package.html description due to the unfortunate layout of the text. Hopefully more people will read the package overview in its present location.
? Add the com.ibm.log4j.net package for doing remote logging using TCP sockets. This is still experimental code.
? Add new debug, .., emerg methods that do not require a category parameter. They assume the "root" category, that is the decision to whether print or not is made by comparing the statement's priority with the default priority.

Release 0.7.4 - 2000-01-21

Type Changes By
? Add a new ILog.init method accepting an Appender and a configuration file as parameters.
? FileAppender's setWriter and setFile methods where not instantiating a new tracer. This caused stack traces to be lost! SyslogAppender had a similar problem.
? The FileAppender and SyslogAppender where not calling the layout's readConfig method to set layout specific options. Thanks to Heinz Richter (heinz.richter@ecmwf.int) for reporting this bug.
? Corrected a bug in Log.log() method where the appender was always called with Priority.DEBUG. Thanks to Oliver Boehm (Oliver.Boehm@abaxx.de) for reporting this bug.

Release 0.7.3 - 2000-01-14

Type Changes By
? Add Syslog compatibility. One can now choose (at runtime) between remote syslog logging or file logging. Syslog logging performance, although not appalling, is significantly slower than file logging.
? Priority class was enriched with the previously missing priorities NOTICE, ALERT and CRIT. The internal constants were also aligned with the syslog counterparts.
? Add the Log.log method to support the new priorities.
? TracerPrintWriter is now an independent class instead of being a nested top-level class in Tracer.
? A number of writers, namely the SyslogWriter, SyslogQuietWriter, SyslogTracerPrintWriter, were added to the helper package.
? Log.force method was removed. The various Appender.doAppend implementations take over its functionality.
? FileAppender and SyslogAppender now use QuietWriter. QuietWriter is a FilterWriter which hides exceptions and instead emits a single warning message to System.err.
? The layout is now an initialization parameter to the appender type. Previously, the layout and the appender where independent parameters to the Log constructor.
? Many small improvements and corrections in the documentation. Syslog related documentation remains sparse.
? ILog.init() and ILog.init(String configFile) have been changed to call ILog.init(,,,) with "com.ibm.log4j.Log.class" as the first parameter. This makes it easier for people to get familiar with log4j.
? Add missing files to the make directory. These files are useful for those wishing to use the log4j make environment. Thanks to "Lee Hall" <LHall@JavaFoundry.com> for reporting this omission. Until recently the make environment failed to compile RMI stubs in a single run. This nagging problem has been corrected thanks to help from Thomas Eirich (IBM Zurich Research Lab).

Release 0.7.2 - 2000-01-04

Type Changes By
? Some users have been rightly complaining about the verbosity TTCCLayout's date output. The full date output is now shortened to "dd MMM YYYY HH:mm:ss.SSS" for example, "06 Nov 1994 08:49:37.459" In addition, users may now choose to print only time information, as in "08:49:37.459".
? The package now uses Writer instead of OutputStream as its output target. This makes the log4j code smaller and easier to understand at the cost of a slight performance degradation. As a result of this change a few method names in FileAppender class were changed.
? Preliminary experiments with SyslogAppedner and SyslogLayout show that syslog compatibility is not far away. The difficultly is adding syslog compatibility without making radical changes to the current log4j architecture.
? Corrected a bug in the NOPLog.createInstance method which always created a Log singleton even if the system property "log4j.logType" was set to NOPLog. Thanks to Robert Gottofrey (Robert.Gottofrey@wdr.com) for reporting this bug and the associated test case.
? Removed the inconsistent "Layout" configuration option in Log.readConfig(). This change should be transparent to most users.

Release 0.7.1 - 1999-12-20

Type Changes By
? The LogCreationManager class has been removed. Its functionality has been transfered to the createInstance and getInstance methods in the Log and NOPLog classes. The new way of creating instances is both simpler and less error prone although just as flexible. As a result of these changes, the init family of methods in the ILog class have been adjusted to the new way of creating the log singleton.
? The Appender interface has been introduced. The method of writing a log statement into an output stream can now be varied by using a different Appender. The new FileAppender offers the same functionality that was previously part of the Log class.
? Changed the time format used in TTCCLayout to be of the form "Day, dd MMM YYYY HH:mm:ss.SSS GMT" for example, "Sun, 06 Nov 1994 22:49:37.459 GMT". This format is almost the same as the format specified in RFC 1123 and also the format recommended in RFC 2616. The only difference is the additional milliseconds information.
? The layout specific options were not read from the configuration file due to a missing instruction. Many thanks to Vikram Sridharan (Vikram.Sridharan@alysis.com) to patiently pointing out this omission to an unbelieving maintainer.

Release 0.7.0 - 1999-12-16

Type Changes By
? Version 0.7.0 and above will be distributed under the IBM Public License (IPL). The IPL is an approved open source license (see http://www.opensource.org/licenses/ for a list). It grants similar rights to the previous ALPHAWORKS license agreement, in particular, the right to redistribute and to modify the package.
? The Log class can now be parameterized with a Layout object. Layouts determine the format of what is printed, where as the Log class decides when to print and to where. As a result of this modularization, the CGULog and NOPCGULog classes no longer exists. CGULog class has been replaced with the TTCCLayout (Time Thread Context Category). This should make it easier to create new log output formats. Some time in the near future, the Log class will be further broken down to allow different strategies for writing to output streams.
? Renamed com.ibm.util.log hierarchy to to com.ibm.log4j. I wanted to do this for some time. I feel release 0.7.0 was the last opportunity to do so. I am sorry for the the trouble caused by this change.
? New NDC class. This class implements nested diagnostic contexts as suggested by Neil Harrison in the article "Patterns for Logging Diagnostic Messages" part of the book "Pattern Languages of Program Design 3" edited by Martin et al. Nested diagnostic contexts is a nifty feature that was missing up to now. The StressNDC test class seems to break JDK 1.2.2 beta on AIX. On Linux and NT using sun's JDK 1.2.2 it seem to work OK. In any case, tests done with StressNDC and associated perl script seem to indicate that the NDC class is bug-free.
? Corrected a date formatting bug in CGULog class where on some environments the wrong month was printed. Thanks to Christopher Williams (Christopher_Williams@mail.northgrum.com) for signaling this bug. Also changed the month format from a number to a three letter abbreviation such as "Jan", "Feb", ..., "Dec". The new format is unambiguous regardless of local date format.

Release 0.6.2 - 1999-12-08

Type Changes By
? Clearer documentation with still much room for improvement.
? Corrected a bug in the Tracer class which always used the Unix line separator instead of the system specific separator. Thanks to Vikram Sridharan (Vikram.Sridharan@alysis.com) for singaling this bug.
? Corrected a runaway comment which gulped the CGULog.readConfig method.
? Add the init family of methods to the ILog class to ease the setup of a basic logging environment. Thanks to Mark Donszelmann (Mark.Donszelmann@cern.ch) for this enhancement.
? Just an hour after releasing version 0.6.1 detected and corrected a bug where the Tracer class would correctly print Exception stack trace but not the type of the Exception. Replaced the distribution on www.zurich.ibm.com without changing the version number. I hope nobody is using the intermediary (and buggy) release of 0.6.1.

Release 0.6.1 - 1999-11-16

Type Changes By
? Better documentation with still much room for improvement.
? For consistence sake, added setDefaultPriority and getDefaultPriority methods to the Category class and deprecated setDefaultPriority in the Log.class.
? Corrected a major bug where if two categories were homonyms the second instance would not be properly initialized.
? Increased the speed of Exception logging from about 4000 microseconds to about 1000. It seems that for some people Exception logging is performance critical. Improved implementation is a variant of Nocolai's (XNH@crisplant.com) implementation.

Release 0.6.0 - 1999-11-09

Type Changes By
? Release of log4j 0.6.0 with incomplete documentation.
? Add a stress test program to debug the new Category class. It turns out that the test program was as hard to get right as the Category class. Given the favorable results of the stress test I am quite confident that the new class is now bug free. This assumption has been proven to be wrong. See above.
? Created a new class called Category to manipulate categories instead of plain Strings. The new class is just as easy to use. However, the evaluation of whether to log or not to log is at least 10 times faster. The NOP class performance remain unaffected by the change. (You can't improve on the performance of an empty function call.) Many thanks to Alex Blewitt "Alex.Blewitt@ioshq.com" for his valuable comments. He was the first to observe that finding Strings in a hash table was an expensive operation. This change will require some recoding on your part. See the FAQ for more details.
? Modified the force in Log and CGULog method to use a byte[] buffer instead of a StringBuffer. The old code was clearer but the new one is at least 25% faster.
? Add regression testing.
? We now enforce a policy where the OutputStream set by setOutputStream is a user managed resource whereas the OutputStream opened using setLogFile is the Log class' responsibility. The setLogFile method now closes any previous OutputStream if only if opened through setLogFile. If the previous OutputStream was opened by the user and set through setOutputStream the previous OutputStream is untouched. Similarly, setOutputStream will close any previous OutputStream if and only if it was opened using setLogFile.
? Add a new method logOutputStreamExists to the Log class allowing the programmer to check if there is already an opened stream before trying to set a new one. A stream can be opened as a byproduct of reading the configuration file.
? Changed the behavior of the (private) Log.Append method in case of failure to write to the OutputStream. Previously, in case of failure, we reverted to System.err. Now, we emit a warning message and discard all future log messages. The new behavior is consistent with our current unreliable logging semantics. The change prevents an otherwise functional program from failing because the terminal is flooded with logging messages.
? Renamed the iLog to ILog to remain consistent with our class naming scheme. The initial intention was to add ILog and deprecate iLog. However, I am running CVS on a fat16 partition, causing serious problems when files differ only in case.
? Corrected a bug where the LogFileName was not remembered. Thanks to Jens for signaling this bug.

Release 0.5a - 1999-10-28

Type Changes By
? Now the programmer can choose to truncate the log file instead of always appending to it. This functionality was first requested and intially implemented by "Jens Uwe Pipka" jens.pipka@gmx.de.
? setLogFile now opens the requested file instead of having the Append function open it later. Cleaned up some related code in the Append function. Although nobody has requested it, there is still no method to close the log file. This is harder to implement reliably than it sounds.
? Simplified setLogOutputStream so that it does no longer return the previously set OutputStream.

Release 0.5 - 1999-10-27

Type Changes By
? Joe Walker (joe@eireneh.com) observed that the LogCreationManager.getSingleton mechanism was cumbersome. There is now a new class iLog (indirect Log) which hides the need to call getSingleton. Performance testing on my 233Mhz Thinkpad shows that this indirection has small performance impact on non-logged calls in the order of 40 nanoseconds. The impact on logged calls is negligible.
? Add a jar file to the distribution. The jar file contains only the files you would need to use log but not other classes needed for testing nor examples.
? Corrected a bug where CGUNOPLog was not integrated to the Makefile.
? Add new public methods isDebugEnabled and isInfoEnabled to allow programmers to check whether a debug/info statement will be logged without incurring the cost of message parameter construction. This addition was suggested by Luke Blanshard Luke@quiq.com.
? Renamed the private method evaluate to isEnabled. Also made it final with no apparent speed gains. In addition, made the Log.force method public.
? New syntactic sugar debug, ..., emerg, methods to log objects.
? Modified the interface to deal with Throwables and not just Exceptions. My thanks to Luke Blanshard for signaling this "bug".
? Add more tests to the LogPerformance class. In particular, to test the influence of indirect debug calls.
? Add a "make" mini-tutorial for those who want to modify the code.
? License updated to standard alphaWorks license allowing modifications to source code. However, this license explicitly requires that modifications be communicated back to alphaWorks.

Release null - 1999-10-15

Type Changes By
? Initial availability on alphaWorks. Refer to the FAQ for the lineage of the package.