SLF4J Class path contains multiple SLF4J bindings

Question

I m getting the following error  It seems there are multiple logging frameworks bound to slf4j  Not sure how to resolve this  Any help is greatly appreciated  SLF4J  Class path contains multiple SLF4J bindings  SLF4J  Found binding in  jar file  C  Users admin  m2 repository org slf4j slf4j-log4j12 1 6 4 slf4j-log4j12-1 6 4 jar  org slf4j impl StaticLoggerBinder class  SLF4J  Found binding in  jar file  C  Users admin  m2 repository org slf4j slf4j-log4j12 1 6 1 slf4j-log4j12-1 6 1 jar  org slf4j impl StaticLoggerBinder class  SLF4J  See http   www slf4j org codes html multiple bindings for an explanation

User · Answer

The error probably gives more information like this (although your jar names could be different)

SLF4J: Found binding in [jar:file:/D:/Java/repository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar!/org/slf4j/impl/StaticLoggerBinder.class] SLF4J: Found binding in [jar:file:/D:/Java/repository/org/apache/logging/log4j/log4j-slf4j-impl/2.8.2/log4j-slf4j-impl-2.8.2.jar!/org/slf4j/impl/StaticLoggerBinder.class]

Noticed that the conflict comes from two jars, named logback-classic-1.2.3 and log4j-slf4j-impl-2.8.2.jar.

Run mvn dependency:tree in this project pom.xml parent folder, giving:

Now choose the one you want to ignore (could consume a delicate endeavor I need more help on this)

I decided not to use the one imported from spring-boot-starter-data-jpa (the top dependency) through spring-boot-starter and through spring-boot-starter-logging, pom becomes:

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-logging</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>

in above pom spring-boot-starter-data-jpa would use the spring-boot-starter configured in the same file, which excludes logging (it contains logback)

User · Answer

Resolved by adding the following exclusion in the dependencies  of pom xml  that caused conflict    lt exclusions gt       lt exclusion gt           lt groupId gt org slf4j lt  groupId gt           lt artifactId gt slf4j-log4j12 lt  artifactId gt       lt  exclusion gt   lt  exclusions gt

User · Answer

Gradle version   configurations all       exclude module   slf4j-log4j12

User · Answer

Just use only required dependency  not all       For me  for normal work of logging process you need this dependency exclude others from pom xml   lt dependency gt           lt groupId gt org slf4j lt  groupId gt           lt artifactId gt slf4j-api lt  artifactId gt           lt version gt 1 7 5 lt  version gt       lt  dependency gt        lt dependency gt           lt groupId gt ch qos logback lt  groupId gt           lt artifactId gt logback-classic lt  artifactId gt           lt version gt 1 1 8 lt  version gt       lt  dependency gt        lt dependency gt           lt groupId gt ch qos logback lt  groupId gt           lt artifactId gt logback-core lt  artifactId gt           lt version gt 1 1 8 lt  version gt       lt  dependency gt

User · Answer

Sbt version   Append exclude  org slf4j    slf4j-log4j12   to the dependency that transitively includes slf4j-log4j12  For example  when using Spark with Log4j 2 6   libraryDependencies     Seq       One SLF4J implementation  log4j-slf4j-impl  is here     org apache logging log4j     log4j-api     2 6 1      org apache logging log4j     log4j-core     2 6 1      org apache logging log4j     log4j-slf4j-impl     2 6 1        The other implementation  slf4j-log4j12  would be transitively      included by Spark  Prevent that with exclude       org apache spark      spark-core     1 5 1  exclude  org slf4j    slf4j-log4j12

User · Answer

1 Finding the conflicting jar If it s not possible to identify the dependency from the warning  then you can use the following command to identify the conflicting jar mvn dependency tree  This will display the dependency tree for the project and dependencies who have pulled in another binding with the slf4j-log4j12 JAR   Resolution  Now that we know the offending dependency  all that we need to do is exclude the slf4j-log4j12 JAR from that dependency  Ex - if spring-security dependency has also pulled in another binding with the slf4j-log4j12 JAR  Then we need to exclude the slf4j-log4j12 JAR from the spring-security dependency    lt dependency gt               lt groupId gt org springframework boot lt  groupId gt               lt artifactId gt spring-boot-starter-security lt  artifactId gt              lt exclusions gt                   lt exclusion gt                       lt groupId gt org springframework boot lt  groupId gt                       lt artifactId gt spring-boot-starter-logging lt  artifactId gt                   lt  exclusion gt               lt  exclusions gt       lt  dependency gt   Note - In some cases multiple dependencies have pulled in binding with the slf4j-log4j12 JAR and you don t need to add exclude for each and every dependency who has pulled in  You just have to do that add exclude dependency with the dependency which has been placed at first  Ex -  lt dependencies gt            lt dependency gt               lt groupId gt org springframework boot lt  groupId gt               lt artifactId gt spring-boot-starter-web lt  artifactId gt               lt exclusions gt                   lt exclusion gt                       lt groupId gt org springframework boot lt  groupId gt                       lt artifactId gt spring-boot-starter-logging lt  artifactId gt                   lt  exclusion gt               lt  exclusions gt           lt  dependency gt            lt dependency gt               lt groupId gt org springframework boot lt  groupId gt               lt artifactId gt spring-boot-starter-security lt  artifactId gt           lt  dependency gt    lt  dependencies gt

User · Answer

I had the same problem  In my pom xml i had both     lt dependency gt           lt groupId gt org slf4j lt  groupId gt           lt artifactId gt slf4j-simple lt  artifactId gt           lt version gt 1 7 28 lt  version gt       lt  dependency gt        lt dependency gt           lt groupId gt org springframework boot lt  groupId gt           lt artifactId gt spring-boot-starter-web lt  artifactId gt           lt version gt 2 2 1 RELEASE lt  version gt       lt  dependency gt    When i deleted the spring-boot-starter-web dependency  problem was solved

User · Answer

The combination of  lt scope gt provided lt  scope gt  and  lt exclusions gt  didn t work for me    I had to use this    lt dependency gt       lt groupId gt ch qos logback lt  groupId gt       lt artifactId gt logback-classic lt  artifactId gt       lt scope gt system lt  scope gt       lt systemPath gt   project basedir  empty jar lt  systemPath gt   lt  dependency gt    Where empty jar is a jar file with literally nothing in it

User · Answer

org codehaus mojo         cobertura-maven-plugin         2 7         test                                       ch qos logback                 logback-classic                                           tools                 com sun                                                               I fixed with this                                      org codehaus mojo         cobertura-maven-plugin         2 7         test                                       ch qos logback                 logback-classic                                           tools                 com sun

User · Answer

For me  it turned out to be an Eclipse Maven issue after switch from log4j to logback  Take a look into your  classpath file and search for the string  log4j    In my case I had the following there    lt classpathentry kind  var  path  M2 REPO org slf4j slf4j-log4j12 1 7 1 slf4j-log4j12-1 7 1 jar   gt   lt classpathentry kind  var  path  M2 REPO log4j log4j 1 2 17 log4j-1 2 17 jar    gt    Removing those entries from the file  or you could regenerate it  fixed the issue

User · Answer

I just ignored removed that jar file

User · Answer

lt  -- lt dependency gt -- gt        lt  -- lt groupId gt org springframework boot lt  groupId gt -- gt        lt  -- lt artifactId gt spring-boot-starter-log4j2 lt  artifactId gt -- gt   lt  -- lt  dependency gt -- gt    I solved by delete this spring-boot-starter-log4j2

User · Answer

Check mvn dependency tree and see if there are multiple repos from where slf4j belongs to two different JARs  If so  add exclusion in one of the dependencies   lt exclusions gt       lt exclusion gt           lt groupId gt org springframework boot lt  groupId gt           lt artifactId gt spring-boot-starter-logging lt  artifactId gt       lt  exclusion gt   lt  exclusions gt

User · Answer

I got this issue in a non-maven project  two depended jar each contained a slf4j  I solved by remove one depended jar  compile the project which of course getting failure  then add the removed one back

User · Answer

This is issue because of StaticLoggerBinder class class belongs to two different jars  this class references from logback-classic-1 2 3 jar and same class also referenced from log4j-slf4j-impl-2 10 0 jar  both of jar in classpath  Hence there is conflict between them   This is reason of log file is not generation even though log4j2 xml  file in classpath  src main resource    We have so select one of jar  I recommend use log4j-slf4j-impl-2 10 0 jar file and exclude logback-classic-1 2 3 jar file  Solution  open pom file and view the dependency Hierarchy  eclipse  or run mvn dependency tree command to find out the dependency tree and source of dependency that download the dependency  find the conflicting dependency and exclude them  For Springboot application try this    lt dependency gt               lt groupId gt org springframework boot lt  groupId gt               lt artifactId gt spring-boot-starter-web lt  artifactId gt               lt exclusions gt                       lt exclusion gt                           lt groupId gt org springframework boot lt  groupId gt                           lt artifactId gt spring-boot-starter-logging lt  artifactId gt                       lt  exclusion gt                   lt  exclusions gt           lt  dependency gt       lt dependency gt               lt groupId gt org springframework boot lt  groupId gt               lt artifactId gt spring-boot-starter-actuator lt  artifactId gt               lt exclusions gt                   lt exclusion gt                       lt groupId gt org springframework boot lt  groupId gt                       lt artifactId gt spring-boot-starter-logging lt  artifactId gt                   lt  exclusion gt               lt  exclusions gt           lt  dependency gt   This is working fine for me after struggling a lots

User · Answer

For me the answer was to force a Maven rebuild  In Eclipse    Right click on project-  Maven -  Disable Maven nature Right click on project-  Spring Tools   Update Maven Dependencies Right click on project-  Configure   Convert Maven Project

User · Answer

Seems removing  m2 directory and     mvn install -DskipTests -T 4 resolved this issue for me

[maven-2] SLF4J: Class path contains multiple SLF4J bindings

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