Detected both log4j-over-slf4j.jar AND slf4j-log4j12.jar on the class path with maven and spring boot

Question

I don't know how do I solve this issue. Please take a look and if possible let me how do I solve it. Here is my pom.xml file.

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.1.5.RELEASE</version>
    <relativePath /> <!-- lookup parent from repository -->
</parent>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-tomcat</artifactId>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>org.apache.tomcat.embed</groupId>
        <artifactId>tomcat-embed-jasper</artifactId>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
    </dependency>


    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-logging</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>javax.inject</groupId>
        <artifactId>javax.inject</artifactId>
        <version>1</version>
    </dependency>
    <dependency>
        <groupId>org.neo4j</groupId>
        <artifactId>neo4j-cypher-compiler-2.1</artifactId>
        <version>2.1.2</version>
    </dependency>
    <dependency>
        <groupId>com.amazonaws</groupId>
        <artifactId>aws-java-sdk</artifactId>
        <version>1.8.9.1</version>
    </dependency>

    <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava</artifactId>
        <version>15.0</version>
    </dependency>
    <dependency>
        <groupId>org.neo4j</groupId>
        <artifactId>neo4j-cypher-compiler-2.0</artifactId>
        <version>2.0.3</version>
    </dependency>

    <dependency>
        <groupId>org.neo4j</groupId>
        <artifactId>neo4j-cypher-compiler-1.9</artifactId>
        <version>2.0.3</version>
    </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>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-log4j</artifactId>
    </dependency>


</dependencies>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <start-class>com.bluepi.util.backup.glacier.Application</start-class>
    <java.version>1.7</java.version>
</properties>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-surefire-plugin</artifactId>
            <configuration>
                <useSystemClassLoader>false</useSystemClassLoader>
            </configuration>
        </plugin>
    </plugins>
</build>

I am basically getting the following error:

Detected both log4j-over-slf4j.jar AND slf4j-log4j12.jar on the class path, preempting StackOverflowError.

See also http://www.slf4j.org/codes.html#log4jDelegationLoop for more details.

Answer 1

You can solve the problem by adding "sl4j over log4j" in pom.xml

Answer 2

Go to your pom.xml and on the bottom tab and click "Dependency Hierarchy" tab. From there search for log4j-over-slf4j. Exclude all instances of this dependency (right click on the instance and "Exclude Maven Artifact"). After you have no more log4j-over-slf4j appearing and have resaved try to run the program. If it still doesn't work then undo the changes you just made (might be smart to backup your pom.xml in the beginning) and exclude all instances of slf4j-log4j12.

I was hitting the same problem when working with Apache Storm . . . an example why one might work and not the other is how Storm pulls in log4j-over-slf4j at runtime despite the fact that I added "Exclude log4j-over-slf4j" to the storm-core dependency