Conflicting modules. LoggerFactory is not a Logback LoggerContext but Logback is on the classpath

Question

I am getting the error found in the title when I try to run my project. I have read other threads on this error, and found a solution that got rid of the error, but killed all my logging.

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

and

<exclusions>
    <exclusion>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
    </exclusion>
</exclusions>

both serve to rid me of the error and kill my logging. I would rather be able to keep my Spring-Boot logging and resolve this problem, but haven't been able to find a solution. Is there a way I can keep my current logging and resolve this dependency issue? What is the best way to track down the offending module?

The full error is:

Exception in thread "main" java.lang.IllegalArgumentException: LoggerFactory is not a Logback LoggerContext but Logback is on the classpath. Either remove Logback or the competing implementation (class org.slf4j.impl.Log4jLoggerFactory loaded from file:/C:/Users/me/.m2/repository/org/slf4j/slf4j-log4j12/1.6.4/slf4j-log4j12-1.6.4.jar). If you are using WebLogic you will need to add 'org.slf4j' to prefer-application-packages in WEB-INF/weblogic.xml: org.slf4j.impl.Log4jLoggerFactory

edit: the pom:

<dependencies>
    <dependency>
        <groupId>com.marklogic</groupId>
        <artifactId>mlcp</artifactId>
        <version>8.0-4</version>
    </dependency>
    <dependency>
        <groupId>org.apache.avro</groupId>
        <artifactId>avro</artifactId>
        <version>1.7.4</version>
    </dependency>
    <dependency>
        <groupId>commons-cli</groupId>
        <artifactId>commons-cli</artifactId>
        <version>1.2</version>
    </dependency>
    <dependency>
        <groupId>commons-codec</groupId>
        <artifactId>commons-codec</artifactId>
        <version>1.4</version>
    </dependency>
    <dependency>
        <groupId>commons-configuration</groupId>
        <artifactId>commons-configuration</artifactId>
        <version>1.6</version>
    </dependency>
    <dependency>
        <groupId>commons-lang</groupId>
        <artifactId>commons-lang</artifactId>
        <version>2.6</version>
    </dependency>
    <dependency>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
        <version>1.1.3</version>
    </dependency>
    <dependency>
        <groupId>commons-modeler</groupId>
        <artifactId>commons-modeler</artifactId>
        <version>2.0.1</version>
    </dependency>
    <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava</artifactId>
        <version>11.0.2</version>
    </dependency>
    <dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-annotations</artifactId>
        <version>2.6.0</version>
    </dependency>
    <dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-auth</artifactId>
        <version>2.6.0</version>
    </dependency>
    <dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-common</artifactId>
        <version>2.6.0</version>
    </dependency>
    <dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-hdfs</artifactId>
        <version>2.6.0</version>
    </dependency>
    <dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-mapreduce-client-common</artifactId>
        <version>2.6.0</version>
    </dependency>
    <dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-mapreduce-client-core</artifactId>
        <version>2.6.0</version>
    </dependency>
    <dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-mapreduce-client-jobclient</artifactId>
        <version>2.6.0</version>
    </dependency>
    <dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-yarn-api</artifactId>
        <version>2.6.0</version>
    </dependency>
    <dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-yarn-common</artifactId>
        <version>2.6.0</version>
    </dependency>
    <dependency>
        <groupId>org.codehaus.jackson</groupId>
        <artifactId>jackson-jaxrs</artifactId>
        <version>1.8.3</version>
    </dependency>
    <dependency>
        <groupId>org.codehaus.jackson</groupId>
        <artifactId>jackson-xc</artifactId>
        <version>1.8.3</version>
    </dependency>
    <dependency>
        <groupId>org.codehaus.jackson</groupId>
        <artifactId>jackson-core-asl</artifactId>
        <version>1.9.13</version>
    </dependency>
    <dependency>
        <groupId>org.codehaus.jackson</groupId>
        <artifactId>jackson-mapper-asl</artifactId>
        <version>1.9.13</version>
    </dependency>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.17</version>
    </dependency>
    <dependency>
        <groupId>com.google.protobuf</groupId>
        <artifactId>protobuf-java</artifactId>
        <version>2.5.0</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.6.1</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.6.4</version>
    </dependency>
    <dependency>
        <groupId>xerces</groupId>
        <artifactId>xercesImpl</artifactId>
        <version>2.10.0</version>
    </dependency>
    <dependency>
        <groupId>xpp3</groupId>
        <artifactId>xpp3</artifactId>
        <version>1.1.3.3</version>
    </dependency>
    <dependency>
        <groupId>org.apache.jena</groupId>
        <artifactId>jena-arq</artifactId>
        <version>2.10.0</version>
    </dependency>
    <dependency>
        <groupId>org.apache.jena</groupId>
        <artifactId>jena-core</artifactId>
        <version>2.10.0</version>
    </dependency>
    <dependency>
        <groupId>org.apache.jena</groupId>
        <artifactId>jena-iri</artifactId>
        <version>0.9.5</version>
    </dependency>
    <dependency>
        <groupId>org.apache.solr</groupId>
        <artifactId>solr-commons-csv</artifactId>
        <version>3.5.0</version>
    </dependency>
    <dependency>
        <groupId>xml-apis</groupId>
        <artifactId>xml-apis</artifactId>
        <version>1.4.01</version>
    </dependency>
    <dependency>
        <groupId>com.thoughtworks.xstream</groupId>
        <artifactId>xstream</artifactId>
        <version>1.4.2</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.11</version>
    </dependency>
    <dependency>
        <groupId>commons-collections</groupId>
        <artifactId>commons-collections</artifactId>
        <version>3.2.1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-yarn-client</artifactId>
        <version>2.6.0</version>
    </dependency>
    <dependency>
        <groupId>com.sun.jersey</groupId>
        <artifactId>jersey-client</artifactId>
        <version>1.9</version>
    </dependency>
    <dependency>
        <groupId>com.sun.jersey</groupId>
        <artifactId>jersey-core</artifactId>
        <version>1.9</version>
    </dependency>
    <dependency>
        <groupId>org.htrace</groupId>
        <artifactId>htrace-core</artifactId>
        <version>3.0.4</version>
    </dependency>
    <dependency>
        <groupId>com.marklogic</groupId>
        <artifactId>marklogic-xcc</artifactId>
        <version>8.0.4</version>
    </dependency>
    <dependency>
        <groupId>com.marklogic</groupId>
        <artifactId>marklogic-mapreduce2</artifactId>
        <version>2.1.4</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

Answer 1

Spring Boot automatically configures the Log Back library because of the web starter. You should exclude the spring-boot-starter-logging to fix the issue.

To exclude the default LogBack configuration in the maven project,

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<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-log4j2</artifactId>
</dependency>

This covers all possible solutions for both Gradle and Maven project.