Spring Boot: multiple SLF4J bindings

Question

This is probably a repeated question, but i can't figure it out where is the binding collision. I have my Spring Boot 1.2.6.RELEASE service and i'm getting this error when i run it:

SLF4J: Class path contains multiple SLF4J bindings. SLF4J: Found binding in [jar:file:/home/jscherman/.m2/repository/ch/qos/logback/logback-classic/1.1.3/logback-classic-1.1.3.jar!/org/slf4j/impl/StaticLoggerBinder.class] SLF4J: Found binding in [jar:file:/home/jscherman/.m2/repository/org/slf4j/slf4j-log4j12/1.7.12/slf4j-log4j12-1.7.12.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 [ch.qos.logback.classic.util.ContextSelectorStaticBinder] 

This is the mvn dependency:tree output

[INFO] com.myenterprise:product-manager:jar:0.0.1-SNAPSHOT [INFO] +- com.myenterprise.product:myproject-api:jar:0.0.1-SNAPSHOT:compile [INFO] +- com.myenterprise.product:myproject-core:jar:0.0.1-SNAPSHOT:compile [INFO] +- org.springframework.boot:spring-boot-starter-web:jar:1.2.6.RELEASE:compile [INFO] |  +- org.springframework.boot:spring-boot-starter-tomcat:jar:1.2.6.RELEASE:compile [INFO] |  |  +- org.apache.tomcat.embed:tomcat-embed-core:jar:8.0.26:compile [INFO] |  |  +- org.apache.tomcat.embed:tomcat-embed-el:jar:8.0.26:compile [INFO] |  |  +- org.apache.tomcat.embed:tomcat-embed-logging-juli:jar:8.0.26:compile [INFO] |  |  \- org.apache.tomcat.embed:tomcat-embed-websocket:jar:8.0.26:compile [INFO] |  +- com.fasterxml.jackson.core:jackson-databind:jar:2.4.6:compile [INFO] |  |  +- com.fasterxml.jackson.core:jackson-annotations:jar:2.4.6:compile [INFO] |  |  \- com.fasterxml.jackson.core:jackson-core:jar:2.4.6:compile [INFO] |  +- org.hibernate:hibernate-validator:jar:5.1.3.Final:compile [INFO] |  |  +- javax.validation:validation-api:jar:1.1.0.Final:compile [INFO] |  |  +- org.jboss.logging:jboss-logging:jar:3.1.3.GA:compile [INFO] |  |  \- com.fasterxml:classmate:jar:1.0.0:compile [INFO] |  +- org.springframework:spring-core:jar:4.1.7.RELEASE:compile [INFO] |  +- org.springframework:spring-web:jar:4.1.7.RELEASE:compile [INFO] |  |  \- org.springframework:spring-aop:jar:4.1.7.RELEASE:compile [INFO] |  \- org.springframework:spring-webmvc:jar:4.1.7.RELEASE:compile [INFO] |     \- org.springframework:spring-expression:jar:4.1.7.RELEASE:compile [INFO] +- org.springframework.boot:spring-boot-starter-data-jpa:jar:1.2.6.RELEASE:compile [INFO] |  +- org.springframework.boot:spring-boot-starter-aop:jar:1.2.6.RELEASE:compile [INFO] |  |  +- org.aspectj:aspectjrt:jar:1.8.6:compile [INFO] |  |  \- org.aspectj:aspectjweaver:jar:1.8.6:compile [INFO] |  +- org.springframework.boot:spring-boot-starter-jdbc:jar:1.2.6.RELEASE:compile [INFO] |  |  +- org.springframework:spring-jdbc:jar:4.1.7.RELEASE:compile [INFO] |  |  +- org.apache.tomcat:tomcat-jdbc:jar:8.0.26:compile [INFO] |  |  |  \- org.apache.tomcat:tomcat-juli:jar:8.0.26:compile [INFO] |  |  \- org.springframework:spring-tx:jar:4.1.7.RELEASE:compile [INFO] |  +- org.hibernate:hibernate-entitymanager:jar:4.3.11.Final:compile [INFO] |  |  +- org.jboss.logging:jboss-logging-annotations:jar:1.2.0.Beta1:compile [INFO] |  |  +- org.hibernate:hibernate-core:jar:4.3.11.Final:compile [INFO] |  |  |  +- antlr:antlr:jar:2.7.7:compile [INFO] |  |  |  \- org.jboss:jandex:jar:1.1.0.Final:compile [INFO] |  |  +- dom4j:dom4j:jar:1.6.1:compile [INFO] |  |  |  \- xml-apis:xml-apis:jar:1.0.b2:compile [INFO] |  |  +- org.hibernate.common:hibernate-commons-annotations:jar:4.0.5.Final:compile [INFO] |  |  +- org.hibernate.javax.persistence:hibernate-jpa-2.1-api:jar:1.0.0.Final:compile [INFO] |  |  \- org.javassist:javassist:jar:3.18.1-GA:compile [INFO] |  +- javax.transaction:javax.transaction-api:jar:1.2:compile [INFO] |  +- org.springframework:spring-orm:jar:4.1.7.RELEASE:compile [INFO] |  +- org.springframework.data:spring-data-jpa:jar:1.7.3.RELEASE:compile [INFO] |  |  +- org.springframework.data:spring-data-commons:jar:1.9.3.RELEASE:compile [INFO] |  |  \- org.slf4j:slf4j-api:jar:1.7.12:compile [INFO] |  \- org.springframework:spring-aspects:jar:4.1.7.RELEASE:compile [INFO] +- mysql:mysql-connector-java:jar:5.1.36:compile [INFO] +- org.flywaydb:flyway-core:jar:3.1:compile [INFO] +- org.springframework.security.oauth:spring-security-oauth2:jar:2.0.7.RELEASE:compile [INFO] |  +- org.springframework:spring-beans:jar:4.1.7.RELEASE:compile [INFO] |  +- org.springframework:spring-context:jar:4.1.7.RELEASE:compile [INFO] |  +- org.springframework.security:spring-security-core:jar:3.2.8.RELEASE:compile [INFO] |  |  \- aopalliance:aopalliance:jar:1.0:compile [INFO] |  +- org.springframework.security:spring-security-config:jar:3.2.8.RELEASE:compile [INFO] |  +- org.springframework.security:spring-security-web:jar:3.2.8.RELEASE:compile [INFO] |  +- commons-codec:commons-codec:jar:1.6:compile [INFO] |  \- org.codehaus.jackson:jackson-mapper-asl:jar:1.9.13:compile [INFO] |     \- org.codehaus.jackson:jackson-core-asl:jar:1.9.13:compile [INFO] +- org.springframework.boot:spring-boot-starter:jar:1.2.6.RELEASE:compile [INFO] |  +- org.springframework.boot:spring-boot:jar:1.2.6.RELEASE:compile [INFO] |  +- org.springframework.boot:spring-boot-autoconfigure:jar:1.2.6.RELEASE:compile [INFO] |  \- org.yaml:snakeyaml:jar:1.14:compile [INFO] +- org.springframework.boot:spring-boot-starter-log4j:jar:1.2.6.RELEASE:compile [INFO] |  +- org.slf4j:jcl-over-slf4j:jar:1.7.12:compile [INFO] |  +- org.slf4j:jul-to-slf4j:jar:1.7.12:compile [INFO] |  +- org.slf4j:slf4j-log4j12:jar:1.7.12:compile [INFO] |  \- log4j:log4j:jar:1.2.17:compile [INFO] \- org.springframework.boot:spring-boot-starter-test:jar:1.2.6.RELEASE:compile [INFO]    +- junit:junit:jar:4.12:compile [INFO]    +- org.mockito:mockito-core:jar:1.10.19:compile [INFO]    |  \- org.objenesis:objenesis:jar:2.1:runtime [INFO]    +- org.hamcrest:hamcrest-core:jar:1.3:compile [INFO]    +- org.hamcrest:hamcrest-library:jar:1.3:compile [INFO]    \- org.springframework:spring-test:jar:4.1.7.RELEASE:compile 

So, apparently the problem is that logback is still in classpath, but i couldn't find it in the output so i don't know where is the problem.

Can you spot the error? I would appreciate your help

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EDIT

This only happens when i run the server as Spring Boot Application. If i run it as java application, the error is gone... any ideas?

Answer 1

I had the exact same problem and could only see the dependency coming from spring boot. It also brought in log4j-over-slf4j, which clashed with my own requirement of slf4j-log4j12. Solved by adding the exclusions below. This is more specific that excluding the spring boot logging.

<dependency>     <groupId>org.springframework.boot</groupId>     <artifactId>spring-boot-starter</artifactId>     <exclusions>         <exclusion>             <artifactId>logback-classic</artifactId>             <groupId>ch.qos.logback</groupId>         </exclusion>         <exclusion>             <artifactId>log4j-over-slf4j</artifactId>             <groupId>org.slf4j</groupId>         </exclusion>     </exclusions> </dependency>