The Apache Log4j 2 team is pleased to announce the Log4j 2.9.1 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.
This release contains bugfixes and minor enhancements.
As of Log4j 2.9.0, the Log4j API was modified to use java.util.ServiceLoader to
locate Log4j implementations, although the former binding mechanism is still
supported. The Log4j jar is now a multi-release jar to provide implementations
of Java 9 specific classes. Multi-release jars are not supported by the OSGi
specification so OSGi modules will not be able to take advantage of these
implementations but will not lose functionality as they will fall back to the
implementations used in Java 7 and 8. More details on the new features and
fixes are itemized below. Note that some tools are not compatible with
multi-release jars and may fail trying to process class files in the
META-INF/versions/9 folder. Those errors should be reported to the tool vendor.
Note that subsequent to the 2.9.0 release, for security reasons,
SerializedLayout is deprecated and no longer used as default in the Socket and
JMS appenders. SerializedLayout can still be used as before, but has to be
specified explicitly. To retain old behaviour, you have to change configuration
like:
<Appenders>
<Socket name="socket" host="localhost" port="9500"/>
</Appenders>
into:
<Appenders>
<Socket name="socket" host="localhost" port="9500">
<SerializedLayout/>
</Socket>
</Appenders>
We do, however, discourage the use of SerializedLayout and recommend JsonLayout
as a replacement:
<Appenders>
<Socket name="socket" host="localhost" port="9500">
<JsonLayout properties="true"/>
</Socket>
</Appenders>
Note that subsequent to the 2.9.0 release, for security reasons, Log4j does not
process DTD in XML files. If you used DTD for including snippets, you have to
use XInclude or Composite Configuration instead.
The Log4j 2.9.1 API, as well as many core components, maintains binary
compatibility with previous releases.
GA Release 2.9.1
Changes in this version include:
Fixed Bugs
LOG4J2-1988: Prevent ConcurrentModificationException with AsyncLoggerConfig.
LOG4J2-1914: Prevent ConcurrentModificationException with AsyncLoggerConfig.
LOG4J2-2048: Increase default queue size for AsyncAppender from 128 to 1024.
LOG4J2-2035: Fix documentation to clarify disruptor-3.3.4 is now required for
async loggers (previously the docs referred to disruptor-3.3.3 which was never
released)
LOG4J2-2030: Inspect all known ClassLoaders to locate the service provider.
LOG4J2-2028: Java 9 StackLocator was not properly skipping the initial stack
frames. Thanks to Jason Tedor.
LOG4J2-2026: java.lang.AbstractMethodError:
javax.xml.parsers.DocumentBuilderFactory.setFeature(). Thanks to Leon Finker.
LOG4J2-2029: Marker examples should not use deprecated flow APIs. Thanks to
Fabrizio Cucci.
LOG4J2-1936: ClassNotFoundException when making all loggers asynchronous under
OSGi environment. Thanks to Helber Belmiro.
Changes
LOG4J2-2023: Use a class' canonical name instead of name to create its logger
name.
LOG4J2-2043: Update Jackson from 2.9.0 to 2.9.1 (fix for Java 9.)
LOG4J2-2044: Update Apache Commons CSV from 1.4 to 1.5.
LOG4J2-2045: Update javax.mail from 1.5.6 to 1.6.0.
LOG4J2-2046: Update Apache Commons Compress from 1.13 to 1.14.
LOG4J2-2047: Update Cassandra driver from 3.1.0 to 3.1.4.
LOG4J2-2049: Update Apache Kafka Client from 0.11.0.0 to 0.11.0.1.
Apache Log4j 2.9.1 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/
