[ANNOUNCEMENT] Apache Log4j 2.12.0 released

[Ralph Goers <rg...@apache.org>]

The Apache Log4j 2 team is pleased to announce the Log4j 2.12.0 release!

Apache Log4j is a well known framework for logging application behavior. 
Log4j 2 is an upgrade to Log4j that provides significant improvements 
over its predecessor, Log4j 1.x, and provides many other modern features 
such as support for Markers, lambda expressions for lazy logging, 
property substitution using Lookups, multiple patterns on a 
PatternLayout and asynchronous Loggers. Another notable Log4j 2 feature 
is the ability to be "garbage-free" (avoid allocating temporary objects) 
while logging. In addition, Log4j 2 will not lose events while 
reconfiguring.

The artifacts may be downloaded 
fromhttps://logging.apache.org/log4j/2.x/download.html.

This release contains bugfixes and minor enhancements.

Due to a break in compatibility in the SLF4J binding, Log4j now ships 
with two versions of the SLF4J to Log4j adapters. log4j-slf4j-impl 
should be used with SLF4J 1.7.x and earlier and log4j-slf4j18-impl 
should be used with SLF4J 1.8.x and later.

New features include support for reconnfiguration of Log4j configuraton 
files accessed via HTTP(s) and Spring Cloud Config specifically, a new 
Docker Lookup for obtaining information about the current Docker 
container, new reconfiguration methods added to the Configurator class, 
the ability to pad integers with leading zeros in filenames generated by 
the rolling file appenders, and allowing the TCP SocketAppender to 
connect to mulitple ip addresses when they are returned from DNS.

More details on the new features and fixes are itemized below.

Note that the XML, JSON and YAML formats changed in the 2.11.0 release: 
they no longer have the "timeMillis" attribute and instead have an 
"Instant" element with "epochSecond" and "nanoOfSecond" attributes.

The Log4j 2.12.0 API, as well as many core components, maintains binary 
compatibility with previous releases.

GA Release 2.12.0

Changes in this version include:

New Features

• LOG4J2-2403: Allow zero padding the counter of a RollingFileAppender. 
Thanks to hupfdule.
• LOG4J2-2427: Add filter that will match events when no marker is 
present. Thanks to Rimaljit Kaur.
• LOG4J2-2406: Add reconfiguration methods to Configurator.
• LOG4J2-913: Add support for reconfiguration via HTTP(S), Docker, and 
Spring Cloud Configuration.
• LOG4J2-2586: TCP Appender should support a host name resolving to 
multiple IP addresses.
• LOG4J2-2337: Allow custom end-of-line with JsonLayout. Thanks to 
Arvind Sahare, Patrice Ferrot.
• LOG4J2-2598: GZIP compression on rollover supports configurable 
compression levels. Thanks to Carter Kozak.
• LOG4J2-2611: AsyncQueueFullPolicy configuration short values "Default" 
and "Discard" are case insensitive to avoid confusion.
• LOG4J2-2634: Add and use method 
org.apache.logging.log4j.message.MapMessage.toKey(String) for simpler 
subclasses.
Fixed Bugs

• LOG4J2-2547: RollingRandomAccessFileAppender error message referenced 
incorrect class name.
• LOG4J2-2616: Restore constructor to ThrowablePatternConverter that was 
removed in 2.8.2.
• LOG4J2-2622: StructuredDataId was ignoring maxLength atribute.
• LOG4J2-2636: RFC5424Layout was not properly setting default Structured 
Element id for the MDC
• LOG4J2-1143: Lookups were not found if the plugin key was not 
lowercase. Thanks to Pascal Heinrich.
• LOG4J2-1852: Locate plugins within a Jar using a URL Connection. 
Thanks to Tanner Altares.
• LOG4J2-2610: Explicitly set file creation time.
• LOG4J2-2561: JEP223 version detection fix for JDK 9 and up. Thanks to 
Ulrich Enslin.
• LOG4J2-1103: FailoverAppender was failing with ERROR appender Failover 
has no parameter that matches element Failovers. Thanks to Seán Dunne.
• LOG4J2-2602: Update file time when size based triggering policy is 
used without a time-based triggering policy.
• LOG4J2-2597: Throw better exception message when both log4j-slf4j-impl 
and log4j-to-slf4j are present.
• LOG4J2-2559: NullPointerException in JdbcAppender.createAppender(). 
Thanks to Li Lei, Gary Gregory.
• LOG4J2-2592: StackOverflowException when server not reachable with 
SocketAppender. Thanks to Dávid Kaya, Gary Gregory.
• LOG4J2-2598: java.lang.StackOverflowError at 
org.apache.logging.log4j.junit.AbstractExternalFileCleaner.println(AbstractExternalFileCleaner.java:169). 
Thanks to Gary Gregory.
• LOG4J2-2564: MapPatternConverter is properly created from the '%K', 
'%map', and '%MAP' patterns. PatternConverter instanceOf methods with 
unknown parameter types no longer elide those with known parameters.
• LOG4J2-2612: NullPointerException at 
org.apache.logging.log4j.core.appender.db.jdbc.JdbcDatabaseManager.writeInternal(JdbcDatabaseManager.java:803).
• LOG4J2-2618: Possible ClassCastException in 
org.apache.logging.log4j.core.script.ScriptManager.ScriptManager(Configuration, 
WatchManager)
• LOG4J2-2631: RoutingAppender PurgePolicy implementations no longer 
stop appenders referenced from the logger configuration, only those that 
have been created by the RoutingAppender. Note that 
RoutingAppender.getAppenders no longer includes entries for referenced 
appenders, only those which it has created.
• LOG4J2-2629: Fix a race allowing events not to be recorded when a 
RoutingAppender purge policy attempts to delete an idle appender at 
exactly the same time as a new event is recorded.
• LOG4J2-2606: Asynchronous logging when the queue is full no longer 
results in heavy CPU utilization and low throughput.
Changes

• : Update tests from H2 1.4.197 to 1.4.199. Thanks to Gary Gregory.
• LOG4J2-2570: Update Jackson from 2.9.7 to 2.9.8. Thanks to Gary Gregory.
• LOG4J2-2574: Update MongoDB 3 module driver from 3.9.0 to 3.10.1. 
Thanks to Gary Gregory.
• LOG4J2-2619: Update Jackson from 2.9.8 to 2.9.9.
• LOG4J2-2634: Refactor several AsyncLogger methods below the 35 byte 
threshold for inlining.
Apache Log4j 2.12.0 requires a minimum of Java 7 to build and run. Log4j 
2.3 was the last release that supported Java 6.

Basic compatibility with Log4j 1.x is provided through the log4j-1.2-api 
component, however it does not implement some of the very implementation 
specific classes and methods. The package names and Maven groupId have 
been changed to org.apache.logging.log4j to avoid any conflicts with 
log4j 1.x.

For complete information on Apache Log4j 2, including instructions on 
how to submit bug reports, patches, or suggestions for improvement, see 
the Apache Apache Log4j 2 website:

https://logging.apache.org/log4j/2.x/