Ultimately if you deduce the problem, file a JIRA issue and share it with me; I will look into it. I care about this matter too; I hate having to exclude logging dependencies on the consuming end.
~ David Smiley Apache Lucene/Solr Search Developer http://www.linkedin.com/in/davidwsmiley On Wed, Jan 15, 2020 at 9:03 PM Wolf, Chris (ELS-CON) <c.w...@elsevier.com> wrote: > I am having several issues due to the slf4j implementation dependency > “log4j-slf4j-impl” being declared as a dependency of solr-core:7.5.0. The > first issue observed when starting the app is this: > > SLF4J: Class path contains multiple SLF4J bindings. > SLF4J: Found binding in > [jar:file:/Users/ma-wolf2/.m2/repository/org/apache/logging/log4j/log4j-slf4j-impl/2.7/log4j-slf4j-impl-2.7.jar!/org/slf4j/impl/StaticLoggerBinder.class] > SLF4J: Found binding in > [jar:file:/Users/ma-wolf2/.m2/repository/ch/qos/logback/logback-classic/1.1.3/logback-classic-1.1.3.jar!/org/slf4j/impl/StaticLoggerBinder.class] > SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an > explanation. > SLF4J: Actual binding is of type > [org.apache.logging.slf4j.Log4jLoggerFactory] > > I first got wind that this might not be just myself from this thread: > > https://lucene.472066.n3.nabble.com/log4j-slf4j-impl-dependency-in-solr-core-td4449635.html#a4449891 > > > * If there are any users that integrate solr-core into their own code, > it's currently a bit of a land-mine situation to change logging > implementations. If there's a way we can include log4j jars at build > time, but remove the log4j dependency on the published solr-core > artifact, that might work well. We should do our best to make it so > people can use EmbeddedSolrServer without log4j jars. > > There are two dimensions to this dependency problem: > > * Building a war file (this runs with a warning) > * Building a spring-boot executable JAR with embedded servlet > container (doesn’t run) > > When building a WAR and deploying, I get the “multiple SLF4J bindings” > warning, but the app works. However, I want the convenience of a > spring-boot executable JAR with embedded servlet container, but in that > case, I get that warning followed by a fatal NoClassDefFoundError/ > ClassNotFoundException – which is a show-stopper. If I hack the built > spring-boot FAT jar and remove “log4j-slf4j-impl.jar” then the app works. > > For the WAR build, the proper version of log4j-slf4j-impl.jar was included > – 2.11.0, but,for some reason when building the spring-boot fat (uber) jar, > it was building with log4j-slf4j-impl:2.7 so of course it will croak. > > There are several issues: > > 1. I don’t want log4j-slf4j-impl at all > 2. Somehow the version of “log4j-slf4j-impl” being used for the build > is 2.7 rather then the expected 2.11.0 > 3. Due to the version issue, the app croaks with > ClassNotFoundException: org.apache.logging.log4j.util.ReflectionUtil > > For issue #1, I tried: > <dependency> > <groupId>org.apache.solr</groupId> > <artifactId>solr-core</artifactId> > <version>7.5.0</version> > <exclusions> > <exclusion> > <artifactId>org.apache.logging.log4j</artifactId> > <groupId>log4j-slf4j-impl</groupId> > </exclusion> > </exclusions> > </dependency> > > All to no avail, as that dependency ends up in the packaged build - for > WAR, it’s version 2.11.0, so even though it’s a bad build, the app runs, > but for building a spring-boot executable JAR with embedded webserver, for > some reason, it switches log4j-slf4j-impl from version 2.11.0 to 2,7 > (2.11.0 works, but should not even be there) > > I also tried this: > > https://docs.spring.io/spring-boot/docs/current/maven-plugin/examples/exclude-dependency.html > > …that didn’t work either. > > I’m thinking that solr-core should have added a classifier of “provided” > for “log4j-slf4j-impl”, but that’s conjecture of a possible solution going > forward, but does anyone know how I can exclude “log4j-slf4j-impl” from a > spring-boot build? > > > > > >
