Apache Logging Services
Log4j 2.10 released
The Apache Log4j 2 team is pleased to announce the Log4j 2.10 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 new features, bugfixes and minor enhancements. Some of the new features include support for the Java 9 module system, support for the new SLF4j 1.8 binding mechanism, simplification of the Log4j property naming scheme, and native support of Jetty's logger. Log4j API is now a fully compliant Java 9 module while the other Log4j jars are Java 9 named automatic modules.
This release supports both SLF4J 1.7.x and SLF4J 1.8.x. Because SLF4J 1.7.x requires implementations to include classes in the org.slf4j.impl package log4j-sl4j-impl cannot be used as a Java 9 module. Support for SLF4J 1.7.x will be removed in a future release.
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 API 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.
During testing of the release it was found that one unit test fails when run on Windows. When building from source either use “
mvn clean install -DskipTests” on Windows or run the build on a different operating system. The unit test failure is a problem in the test, not in Log4j. As always, pre-built distributions can be downloaded from http://www.apache.org/dist/logging/log4j/ or the binaries jars may be obtained from the Maven central repository.