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.
Resolved by adding the following exclusion in the dependencies (of pom.xml) that caused conflict.
<exclusions>
<exclusion>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
</exclusion>
</exclusions>
Gradle version;
configurations.all {
exclude module: 'slf4j-log4j12'
}
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)
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")
)
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.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
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 that has pulled in.
You just have to do that add exclude dependency with the dependency which has been placed at first.
Ex -
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</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-security</artifactId>
</dependency>
</dependencies>
If you work with gradle then add following code to your build.gradle file to exclude SLF4J binding from all the modules
configurations.all {
exclude group: 'org.springframework.boot', module: 'spring-boot-starter-logging'
}
I just ignored/removed that jar file.
<!--<dependency>-->
<!--<groupId>org.springframework.boot</groupId>-->
<!--<artifactId>spring-boot-starter-log4j2</artifactId>-->
<!--</dependency>-->
I solved by delete this:spring-boot-starter-log4j2
Just use only required dependency, not all :))). For me, for normal work of logging process you need this dependency exclude others from pom.xml
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.5</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.1.8</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-core</artifactId>
<version>1.1.8</version>
</dependency>
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.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</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-actuator</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
This is working fine for me after struggling a lots.
...
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
...
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:
<classpathentry kind="var" path="M2_REPO/org/slf4j/slf4j-log4j12/1.7.1/slf4j-log4j12-1.7.1.jar"/>
<classpathentry kind="var" path="M2_REPO/log4j/log4j/1.2.17/log4j-1.2.17.jar" />
Removing those entries from the file (or you could regenerate it) fixed the issue.
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
I solved this by going to Project Structure from my Intellij project.
I deleted the file named: Maven: org.apache.logging.log4j:log4j-to-slf4j-impl:2.14.1
This file is not shown in this picture. You may see two libraries mentioned as log4j-to-slf4j. Delete one and you are good to go.
For all those looking for the solution for spring-boot-type dependencies, the magic incantation for Gradle is this:
configurations.all {
exclude group: 'ch.qos.logback', module: 'logback-classic'
}
in your build.gradle at the top level (not inside the dependencies block).
All other solutions found in the interwebs (including the one here suggesting to exclude the slf4j module) did not work for me.
This is what I have in my build.gradle (snippet):
// Removes the annoying warning about the multiple SLF4J implementations:
// SLF4J: Class path contains multiple SLF4J bindings.
configurations.all {
exclude group: 'ch.qos.logback', module: 'logback-classic'
}
dependencies {
annotationProcessor "org.springframework.boot:spring-boot-configuration-processor"
implementation ('org.springframework.boot:spring-boot-starter-actuator')
implementation ('org.springframework.boot:spring-boot-starter-data-mongodb-reactive')
implementation ('org.springframework.boot:spring-boot-starter-webflux')
annotationProcessor "org.projectlombok:lombok:${lombokVersion}"
compileOnly "org.projectlombok:lombok:${lombokVersion}"
// Removes the annoying warning:
// warning: unknown enum constant When.MAYBE
// reason: class file for javax.annotation.meta.When not found
// See: https://stackoverflow.com/questions/29805622/could-not-find-or-load-main-class-org-gradle-wrapper-gradlewrappermain/31622432
implementation group: 'com.google.code.findbugs', name: 'jsr305', version: '3.0.2'
// other stuff...
YMMV
I had the same problem. In my pom.xml i had both
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.7.28</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>2.2.1.RELEASE</version>
</dependency>
When i deleted the spring-boot-starter-web dependency, problem was solved.
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.
In case these logs are the result of this fix:
https://stackoverflow.com/a/9919375/2894819
When one of your libraries actually use it. And your application doesn't need SL4J just replace implementation to runtimeOnly.
// contains dependency to sl4j-api
implementation("com.github.doyaaaaaken:kotlin-csv-jvm:1.2.0")
// add this to remove both warnings
runtimeOnly("org.slf4j:slf4j-nop:1.7.36")
In that case when you run your app the actual dependency will be included once by the library and won't be included to the bundle of your application.jar itself.
In my case I had 2 sources of dependencies for log4 one in C:\Program Files\smcf.ear directory and the second from maven which caused the multiple binding for sl4j.
Deleting the smcf.ear directory solved the issue for me.
The combination of <scope>provided</scope> and <exclusions> didn't work for me.
I had to use this:
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<scope>system</scope>
<systemPath>${project.basedir}/empty.jar</systemPath>
</dependency>
Where empty.jar is a jar file with literally nothing in it.
Seems removing .m2 directory and :
mvn install -DskipTests -T 4 resolved this issue for me.
My situation is a bit strange:
Dependency with artifact id: yyy in the pom (see below) has dependency:
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>2.5</version>
</dependency>
So the problem is I need to use the 3.1.0 version in the current module because it has extra functionality:
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
I have tried the exclusions tag and dependencymanagement tag explained in the example on the page: Maven: how to override the dependency added by a library
It does not work. I have also read and tried the 3 examples in this article: https://spring.io/blog/2016/04/13/overriding-dependency-versions-with-spring-boot
It also did not work. So what I did was to re-order my pom dependencies so that the 3.1.0 goes before the one with artifact yyy and I was happy it worked I built successfully a clean install. My happiness was short lived because after a clean install the pom re-ordered itself and the 3.1.0 was automatically re-ordered back below the yyy. Which means the next build will use 2.5 again and fail.
My pom structure snippet is as below:
<dependencies>
<dependency>
<groupId>xxxx.xxx.xxxx</groupId>
<artifactId>yyy</artifactId>
<version>1.0.0</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
<dependencies>
My happiness was short lived because after a clean install the pom
re-ordered itself and the 3.1.0 was automatically re-ordered back
below the yyy. Which means the next build will use 2.5 again and fail.
Note that the javax.servlet:javax.servlet-api has to be included in a WAR but only in a standalone JAR that includes and bootstraps a servlet container.
If you build a standard WAR you have to use the dependency provided by the server. So the dependency should be declared with the provided scope.
I have tried the exclusions tag and dependencymanagement tag explained
in the example on the page: Maven: how to override the dependency
added by a library
dependencyManagement will be helpless here as the issue is related to a dependency you include outside the dependencyManagement element.
But using the exclusions option in the dependency declaration is the right way. It should exclude the 2.5 version of the javax.servlet-api artifact if used in this way :
<dependencies>
<dependency>
<groupId>xxxx.xxx.xxxx</groupId>
<artifactId>yyy</artifactId>
<version>1.0.0</version>
<exclusions>
<exclusion>
<artifactId>javax.servlet</artifactId>
<groupId>javax.servlet-api</groupId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
</dependencies>
If the problem persists it means that the dependency is probably pulled by another dependency.
Some hints that generally help to discover that :
check that you don't use WAR overlay feature. But not likely here as you retrieve only 1 version of the dependency
use mvn dependency:tree on the WAR project to inspect all pulled dependencies.
To ease the readable you can also filter in this way :
mvn dependency:tree -Dincludes=javax.javax.servlet-api
The solution below has ignored the version 2.5 and so it is working. However i don't know what it means. Does it remove other dependencies? Please interpret what the asterix in groupId and artifactId mean in simple english. I want to know the risks because i am using a multi module system where there to many nested dependencies in other dependencies. I will continue to research as of now but if anyone can explain please do. Thanks
<dependencies>
<dependency>
<groupId>xxxx.xxx.xxxx</groupId>
<artifactId>yyy</artifactId>
<version>1.0.0</version>
<exclusions>
<exclusion>
<groupId>javax.servlet</groupId> // this works or
<groupId>*</groupId> // this works
<artifactId>*</artifactId> // this part was a mandatory *
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
</dependencies>
I want to use the last version of the powermock library (1.6.5) through Maven. But My package cannot be compiled, since Maven finds dependency Convergence error. Below you can see that there are 2 different versions of org.objenesis:objenesis library in the same dependency:
Dependency convergence error for org.objenesis:objenesis:2.1 paths to
dependency are:
+-mypackage:v1-SNAPSHOT
+-org.powermock:powermock-api-mockito:1.6.5
+-org.mockito:mockito-core:1.10.19
+-org.objenesis:objenesis:2.1
and
+-mypackage:v1-SNAPSHOT
+-org.powermock:powermock-api-mockito:1.6.5
+-org.powermock:powermock-api-mockito-common:1.6.5
+-org.powermock:powermock-api-support:1.6.5
+-org.powermock:powermock-reflect:1.6.5
+-org.objenesis:objenesis:2.2
I tried to make an exclusion, but I cannot exclude only one version, I need to exclude all of them, which does not pass me, as I think.
Did you have the same problem? What can I do?
There two different version of objenesis, because two different libraries depends on two different version ofobjenesis`: PowerMock and Mockito. You have two options to resolve the issue:
Exclude org.objenesis:objenesis from PowerMock dependencies and add it manually to your pom.
Exclude mockito-core from PowerMock dependencies and add it as separated decency to your pom with excluding objenesis.
I followed the answer from Arthur, but only made an exclusion for objenesis to the powermock-module-junit dependency. After that the enforcer plugins was happy.
<dependency>
<groupId>org.powermock</groupId>
<artifactId>powermock-module-junit4</artifactId>
<version>1.7.0</version>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.objenesis</groupId>
<artifactId>objenesis</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.powermock</groupId>
<artifactId>powermock-api-mockito2</artifactId>
<version>1.7.0</version>
<scope>test</scope>
</dependency>
I have a Java Maven project that I developed a while ago and that doesn't work anymore. It uses a parent pom together with another Maven project in which I think the Jena version was changed and it also uses an external library that uses Jena. The Maven dependency is:
<dependency>
<groupId>com.hp.hpl.jena</groupId>
<artifactId>jena</artifactId>
<version>2.6.4</version>
</dependency>
When I execute my tests I get the following errors:
java.lang.NoClassDefFoundError: Could not initialize class
com.hp.hpl.jena.query.ARQ
java.lang.NoClassDefFoundError: org/apache/jena/iri/IRIFactory
at org.openjena.riot.system.PrefixMap.add(PrefixMap.java:54)
at com.hp.hpl.jena.sparql.util.MappingRegistry.addPrefixMapping(MappingRegistry.java:33)
at com.hp.hpl.jena.query.ARQ.init(ARQ.java:449) [...]
The errors are not thrown by my code directly but by the library I include. Can I prevent this by downgrading the Jena version in the parent pom or what can I do here?
P.S.: I now have a minimal code example that reproduces the error (java.lang.NoClassDefFoundError: org/apache/jena/iri/IRIFactory):
import org.junit.Test;
import com.hp.hpl.jena.query.ARQ;
public class DependencyTest
{
#Test
public void testARQ()
{
ARQ a = new ARQ();
}
}
And I guess it comes from this dependency:
<dependency>
<groupId>org.apache.jena</groupId>
<artifactId>jena-arq</artifactId>
<version>2.9.1-incubating-SNAPSHOT</version>
</dependency>
I know there is probably a factory instead of a constructor but I guess this still shows where the problem is.
P.S.: I noticed that I had the dependencies "jena", "arq" and "jena-arq":
<dependency>
<groupId>com.hp.hpl.jena</groupId>
<artifactId>arq</artifactId>
<version>2.8.8</version>
</dependency>
<dependency>
<groupId>org.apache.jena</groupId>
<artifactId>jena-arq</artifactId>
<version>2.9.1-incubating-SNAPSHOT</version>
</dependency>
dependency>
<groupId>com.hp.hpl.jena</groupId>
<artifactId>jena</artifactId>
<version>2.6.4</version>
</dependency>
So I thought maybe I have too much overlapping dependencies and commented out "jena" and "arq". But I still get the error
java.lang.NoClassDefFoundError: Could not initialize class com.hp.hpl.jena.query.ARQ
at com.hp.hpl.jena.sparql.engine.http.QueryEngineHTTP.<init> [...]
I also tried out forcing a non-snapshot-version 2.9.0-incubating, but then I still get the NoClassDefFoundError with and without using the "jena" and "arq"-dependencies.
P.P.S.:
I still get the same error even when I use the following dependencies:
<dependency>
<groupId>org.apache.jena</groupId>
<artifactId>jena-arq</artifactId>
<version>2.9.0-incubating</version>
</dependency>
<dependency>
<groupId>org.apache.jena</groupId>
<artifactId>jena-core</artifactId>
<version>2.7.0-incubating</version>
</dependency>
<dependency>
<groupId>org.apache.jena</groupId>
<artifactId>jena-iri</artifactId>
<version>2.7.0-incubating</version>
</dependency>
You can search for the missing class using the Maven Central search application
http://search.maven.org/#search|ga|1|fc%3A%22com.hp.hpl.jena.query.ARQ%22
It demonstrates that the dependency you appear to be missing is:
<dependency>
<groupId>com.hp.hpl.jena</groupId>
<artifactId>arq</artifactId>
<version>2.6.0</version>
</dependency>
Doesn't appear to be a version 2.6.4, but you're probabily best advised to go for a more modern version (This project was recently donated to apache)
Instructions for using Apache Jena with Maven are here:
incubator.apache.org/jena/download/maven.html
Specifying ARQ 2.9.0 as a dependency in your project pom.xml will pull in the other Jena components that you need.
I finally resolved this error by excluding the "jena"-Dependency brought in as a transitive dependency from some library.
I have a case that I have the following cyclic dependencies in maven:
JAR A version 1.1 depends on JAR B version 1.0
JAR B version 1.1 depends on JAR A version 1.0
For some reason that I don't know, Maven brings all the 4 JARs: A 1.0, A 1.1, B 1.0 and B 1.1, which results in a classpath conflict.
This really sucks. I already ask the developers of both JARs to fix this, however I can't simply sit and wait for the day that they decide to fix this.
I tried this:
<dependency>
<groupId>groupA</groupId>
<artifactId>artifactA</artifactId>
<version>1.1</version>
<type>pom</type>
<scope>compile</scope>
<exclusions>
<exclusion>
<groupId>groupB</groupId>
<artifactId>artifactB</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>groupB</groupId>
<artifactId>artifactB</artifactId>
<version>1.1</version>
<type>pom</type>
<scope>compile</scope>
<exclusions>
<exclusion>
<groupId>groupA</groupId>
<artifactId>artifactA</artifactId>
</exclusion>
</exclusions>
</dependency>
The result is that maven excludes all of the JARs as if none dependency were added, and the project does not compiles because there are missing classes.
So, other than just asking both JARs developers to solve this, what can I do? How can I import both the new dependencies while leaving out both the old ones?
Pragmatic solution would be to redeclare the unwanted dependencies as provided, for example:
<dependency>
<groupId>groupA</groupId>
<artifactId>artifactA</artifactId>
<version>1.0</version>
<scope>provided</scope>
</dependency>
I'm not particularly fond of using provided in such manner, since it leaves the dependency in the compile time and could lead to unwanted compile dependencies, but I see no other way in your case ;(.