Major Description
It seems that sometime between versions 1.7.0 and 1.12.0 of org.apache.kudu:kudu-spark2_2.11, some SLF4J classes started being included.
# for 1.7.0 jar tvf ~/.m2/repository/org/apache/kudu/kudu-spark2_2.11/1.7.0/kudu-spark2_2.11-1.7.0.jar | grep slf4j 1203 Wed Jun 29 14:43:04 CDT 2016 META-INF/license/LICENSE.slf4j.txt #for 1.12.0 jar tvf ~/.m2/repository/org/apache/kudu/kudu-spark2_2.11/1.12.0/kudu-spark2_2.11-1.12.0.jar | grep slf4j 0 Mon Apr 27 14:53:30 CDT 2020 org/slf4j/ 0 Mon Apr 27 14:53:30 CDT 2020 org/slf4j/event/ 555 Mon Dec 16 22:03:32 CST 2019 org/slf4j/event/EventConstants.class 9842 Mon Dec 16 22:03:32 CST 2019 org/slf4j/event/EventRecodingLogger.class 1450 Mon Dec 16 22:03:32 CST 2019 org/slf4j/event/Level.class 432 Mon Dec 16 22:03:32 CST 2019 org/slf4j/event/LoggingEvent.class 2615 Mon Dec 16 22:03:32 CST 2019 org/slf4j/event/SubstituteLoggingEvent.class 0 Mon Apr 27 14:53:30 CDT 2020 org/slf4j/helpers/ 3285 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/BasicMarker.class 1634 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/BasicMarkerFactory.class 1233 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/BasicMDCAdapter$1.class 2618 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/BasicMDCAdapter.class 1091 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/FormattingTuple.class 4773 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/MarkerIgnoringBase.class 7553 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/MessageFormatter.class 823 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/NamedLoggerBase.class 3267 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/NOPLogger.class 584 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/NOPLoggerFactory.class 1249 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/NOPMDCAdapter.class 10262 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/SubstituteLogger.class 2199 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/SubstituteLoggerFactory.class 196 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/Util$1.class 765 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/Util$ClassContextSecurityManager.class 2952 Mon Dec 16 22:03:32 CST 2019 org/slf4j/helpers/Util.class 180 Mon Dec 16 22:03:32 CST 2019 org/slf4j/ILoggerFactory.class 272 Mon Dec 16 22:03:32 CST 2019 org/slf4j/IMarkerFactory.class 1375 Mon Dec 16 22:03:32 CST 2019 org/slf4j/Logger.class 12575 Mon Dec 16 22:03:32 CST 2019 org/slf4j/LoggerFactory.class 666 Mon Dec 16 22:03:32 CST 2019 org/slf4j/Marker.class 1621 Mon Dec 16 22:03:32 CST 2019 org/slf4j/MarkerFactory.class 177 Mon Dec 16 22:03:32 CST 2019 org/slf4j/MDC$1.class 749 Mon Dec 16 22:03:32 CST 2019 org/slf4j/MDC$MDCCloseable.class 3675 Mon Dec 16 22:03:32 CST 2019 org/slf4j/MDC.class 0 Mon Apr 27 14:53:30 CDT 2020 org/slf4j/spi/ 455 Mon Dec 16 22:03:32 CST 2019 org/slf4j/spi/LocationAwareLogger.class 249 Mon Dec 16 22:03:32 CST 2019 org/slf4j/spi/LoggerFactoryBinder.class 249 Mon Dec 16 22:03:32 CST 2019 org/slf4j/spi/MarkerFactoryBinder.class 529 Mon Dec 16 22:03:32 CST 2019 org/slf4j/spi/MDCAdapter.class 0 Mon Apr 27 14:53:30 CDT 2020 META-INF/maven/org.slf4j/ 0 Mon Apr 27 14:53:30 CDT 2020 META-INF/maven/org.slf4j/slf4j-api/ 3835 Mon Dec 16 21:59:52 CST 2019 META-INF/maven/org.slf4j/slf4j-api/pom.xml 109 Mon Dec 16 22:00:08 CST 2019 META-INF/maven/org.slf4j/slf4j-api/pom.properties
These should be removed from the jar, or at least relocated so as not to clash with Spark vendor dependencies, which can cause LinkageError in Spark clusters. Real life example of this problem, seen on a Spark job started on CDH 6.3 cluster:
Exception in thread "main" java.lang.LinkageError: loader constraint violation: when resolving method "org.slf4j.impl.StaticLoggerBinder.getLoggerFactory()Lorg/slf4j/ILoggerFactory;" the class loader (instance of org/apache/spark/util/ChildFirstURLClassLoader) of the current class, org/slf4j/LoggerFactory, and the class loader (instance of sun/misc/Launcher$AppClassLoader) for the method\'s defining class, org/slf4j/impl/StaticLoggerBinder, have different Class objects for the type org/slf4j/ILoggerFactory used in the signature at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:423) at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:362) at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:388)