I am using Spring boot. Spring boot by default comes with logback. I wanted to use log4j (for whatever reasons..)
In order to do that I had to exclude logback and add new log4j dependencies:
Logback is “hidden” inside this package:
1 2 3 4 5 6 | compile("org.springframework.boot:spring-boot-starter:$project.ext.springBootVersion") { exclude module: 'org.springframework.boot:spring-boot-starter-logging'}compile("org.springframework.boot:spring-boot-starter-log4j:$project.ext.springBatchVersion") |
Now when you try to run app you get this Exception:
1 2 3 | SLF4J: Class path contains multiple SLF4J bindings.SLF4J: Found binding in [jar:file:/C:/dev/caches/modules-2/files-2.1/org.slf4j/slf4j-log4j12/1.7.10/b3eeae7d1765f988a1f45ea81517191315c69c9e/slf4j-log4j12-1.7.10.jar!/org/slf4j/impl/StaticLoggerBinder.class]SLF4J: Found binding in [jar:file:/C:/dev/caches/modules-2/files-2.1/ch.qos.logback/logback-classic/1.1.2/b316e9737eea25e9ddd6d88eaeee76878045c6b2/logback-classic-1.1.2.jar!/org/slf4j/impl/StaticLoggerBinder.class] |
Now we have to look at Gradle’s dependencies tree to see where logback is hidden in order to eliminate it.
Simple command to see gradle’s dependencies tree:
1 | gradle -q dependencies web:dependencies --configuration compile |
* web stands for your module name.
Snap view of the output:
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | Project :web - web ------------------------------------------------------------ compile - Compile classpath for source set 'main'. +--- org.springframework.boot:spring-boot-starter-actuator:1.2.2.RELEASE | +--- org.springframework.boot:spring-boot-starter:1.2.2.RELEASE | | +--- org.springframework.boot:spring-boot:1.2.2.RELEASE | | | +--- org.springframework:spring-core:4.1.5.RELEASE | | | | \--- commons-logging:commons-logging:1.2 | | | \--- org.springframework:spring-context:4.1.5.RELEASE | | | +--- org.springframework:spring-aop:4.1.5.RELEASE | | | | +--- aopalliance:aopalliance:1.0 | | | | +--- org.springframework:spring-beans:4.1.5.RELEASE | | | | | \--- org.springframework:spring-core:4.1.5.RELEASE (*) | | | | \--- org.springframework:spring-core:4.1.5.RELEASE (*) | | | +--- org.springframework:spring-beans:4.1.5.RELEASE (*) | | | +--- org.springframework:spring-core:4.1.5.RELEASE (*) | | | \--- org.springframework:spring-expression:4.1.5.RELEASE | | | \--- org.springframework:spring-core:4.1.5.RELEASE (*) | | +--- org.springframework.boot:spring-boot-autoconfigure:1.2.2.RELEASE | | | +--- org.springframework.boot:spring-boot:1.2.2.RELEASE (*) | | | \--- org.yaml:snakeyaml:1.14 | | +--- org.springframework.boot:spring-boot-starter-logging:1.2.2.RELEASE | | | +--- org.slf4j:jcl-over-slf4j:1.7.10 | | | | \--- org.slf4j:slf4j-api:1.7.10 | | | +--- org.slf4j:jul-to-slf4j:1.7.10 | | | | \--- org.slf4j:slf4j-api:1.7.10 | | | +--- org.slf4j:log4j-over-slf4j:1.7.10 | | | | \--- org.slf4j:slf4j-api:1.7.10 | | | \--- mycompany:logback-classic:1.1.2 | | | +--- mycompany:logback-core:1.1.2 | | | \--- org.slf4j:slf4j-api:1.7.6 -> 1.7.10 | | +--- org.springframework:spring-core:4.1.5.RELEASE (*) | | \--- org.yaml:snakeyaml:1.14 | +--- org.springframework.boot:spring-boot-actuator:1.2.2.RELEASE |
We can find one of the instances of logback popping up from one of our dependencies:
1 | mycompany:logback-core:1.1.2 |
(I found logback show’s in other dependencies).
Now we have two options:
- Exclude each logback’s route with-in the indecencies tree
- Use configuration-wide exclusion (the easier way)
So go to your build.gradle and add this:
1 2 3 | configurations { compile.exclude group:'ch.qos.logback'} |
Thats it. Your nightmare is over. If you check the dependencies tree again you wont see any existence of logback anymore.
| Reference: | How to exclude libraries from all dependencies in Gradle from our JCG partner Idan Fridman at the IdanFridman.com blog. |
