How to fix "SLF4J: class path contains multiple SLF4J bindings" when starting game 2.3.x?

Question

I updated my version of Play and other libraries, and now I see the following:

SLF4J: Class path contains multiple SLF4J bindings. SLF4J: Found binding in [jar:file:/home/paul/.ivy2/cache/org.slf4j/slf4j-nop/jars/slf4j-nop-1.7.7.jar!/org/slf4j/impl/StaticLoggerBinder.class] SLF4J: Found binding in [jar:file:/home/paul/.ivy2/cache/org.slf4j/slf4j-jdk14/jars/slf4j-jdk14-1.7.7.jar!/org/slf4j/impl/StaticLoggerBinder.class] SLF4J: Found binding in [jar:file:/home/paul/.ivy2/cache/org.slf4j/slf4j-simple/jars/slf4j-simple-1.7.7.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.slf4j.helpers.NOPLoggerFactory] 

I try to keep track of where they come from, but when I run show managed-classpath , the only banks are slf4j

 /home/paul/.ivy2/cache/org.slf4j/slf4j-api/jars/slf4j-api-1.7.6.jar /home/paul/.ivy2/cache/org.slf4j/jul-to-slf4j/jars/jul-to-slf4j-1.7.6.ja /home/paul/.ivy2/cache/org.slf4j/jcl-over-slf4j/jars/jcl-over-slf4j-1.7.6.jar 

I never see slf4j-nop-1.7.7.jar or slf4j-jdk14-1.7.7.jar or slf4j-simple-1.7.7.jar .

How do they relate to the class path?

Answer 1

After comments and possible solutions, I can offer mine for inclusion in build.sbt for users of versions without correction, for example. Game 2.3.2:

 libraryDependencies ++= Seq( "org.slf4j" % "slf4j-api" % "1.7.7", "org.slf4j" % "jcl-over-slf4j" % "1.7.7" ).map(_.force()) libraryDependencies ~= { _.map(_.exclude("org.slf4j", "slf4j-jdk14")) } 

Before:

 --- (Running the application from SBT, auto-reloading is enabled) --- [info] play - Listening for HTTP on /0:0:0:0:0:0:0:0:9000 (Server started, use Ctrl+D to stop and go back to the console...) SLF4J: Class path contains multiple SLF4J bindings. SLF4J: Found binding in [jar:file:/Users/jacek/.ivy2/cache/org.slf4j/slf4j-nop/jars/slf4j-nop-1.7.7.jar!/org/slf4j/impl/StaticLoggerBinder.class] SLF4J: Found binding in [jar:file:/Users/jacek/.ivy2/cache/org.slf4j/slf4j-jdk14/jars/slf4j-jdk14-1.7.7.jar!/org/slf4j/impl/StaticLoggerBinder.class] SLF4J: Found binding in [jar:file:/Users/jacek/.ivy2/cache/org.slf4j/slf4j-simple/jars/slf4j-simple-1.7.7.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.slf4j.helpers.NOPLoggerFactory] [info] play - Application started (Dev) 

After (with change):

 --- (Running the application from SBT, auto-reloading is enabled) --- [info] play - Listening for HTTP on /0:0:0:0:0:0:0:0:9000 (Server started, use Ctrl+D to stop and go back to the console...) [info] play - Application started (Dev) 

These are the project dependencies:

$ show libraryDependencies [info] List(org.scala-lang:scala-library:2.11.2, com.typesafe.play:twirl-api:1.0.2, com.typesafe.play:play:2.3.2, com.typesafe.play:play-test:2.3.2:test, com.typesafe.play:play-docs:2.3.2:docs, com.typesafe.play:play-jdbc:2.3.2, com.typesafe.play:anorm:2.3.2, com.typesafe.play:play-cache:2.3.2, com.typesafe.play:play-ws:2.3.2, com.typesafe.play:filters-helpers:2.3.2, org.webjars:webjars-play:2.3.0, org.webjars:requirejs:2.1.14-1, org.webjars:underscorejs:1.6.0-3, org.webjars:jquery:2.1.1, org.webjars:bootstrap:3.2.0, org.webjars:angularjs:1.3.0-beta.17, org.postgresql:postgresql:9.3-1102-jdbc41, org.slf4j:slf4j-api:1.7.7, org.slf4j:jcl-over-slf4j:1.7.7)