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Comment: Futher cleanup for maven, added gradle section

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Following sections shows how to configure different logging solutions/backends dependencies to avoid conflicts. Loggers configuration are out of scope of this document, you should look at relevant library documentation.

Example configuration for Apache Tika 2.5.0+ (Apache Maven)

If you use Apache Maven dependency section in pom.xml will contain something like this:

...

<!-- Merge with your properties section -->
<properties>
  <!-- components versions, feel free keep only required for your case -->
  <tika.version>2.6.0</tika.version>
  <slf4j.version>2.0.3</slf4j.version>
  <log4j2.version>2.19.0</log4j2.version>
  <logback.version>1.4.4</logback.version> <!-- 1.4.4 for Jakarta EE 9+ or 1.3.4 if you use Java EE or Jakarta EE 8 -->
  <reload4j.version>1.2.22</reload4j.version>
</properties>

<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>org.apache.tika</groupId>
      <artifactId>tika-bom</artifactId>
      <version>${tika.version}</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-bom</artifactId>
      <version>${log4j2.version}</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

<!-- Merge with your dependencies section -->
<dependencies>
  <dependency>
    <groupId>org.apache.tika</groupId>
    <artifactId>tika-core</artifactId>
  </dependency>
  <dependency>
    <groupId>org.apache.tika</groupId>
    <artifactId>tika-parsers-standard-package</artifactId>
    <exclusions>
      <!--
        This exclusions will become obsolete at some point but better to keep it now.
        tika-parser-*-module should excludesexclude commons-logging explicitly but upstream libraries
        may add it to their direct or transitive dependencies
      -->
      <exclusion>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
      </exclusion>


      <exclusion>
<!--
        <groupId>log4j</groupId>
These exclusions aren't necessary for tika-parsers-standard-package 
  <artifactId>log4j</artifactId>
      </exclusion>
but may be required for other <exclusion>
artifacts to have explicit logging configuration
   <groupId>ch.qos.logback</groupId>
     and avoid  <artifactId>logback-core</artifactId>
 logging backend loops.
     </exclusion>
  -->
      <exclusion>
        <groupId>org.slf4j<<groupId>log4j</groupId>
        <artifactId>slf4j-reload4j<<artifactId>log4j</artifactId>
      </exclusion>

      <exclusion>

        <groupId>ch<groupId>org.qos.logback<slf4j</groupId>

        <artifactId>logback<artifactId>slf4j-classic<log4j12</artifactId>

      </exclusion>
      <exclusion>
        <groupId>ch<groupId>org.qos.reload4j<slf4j</groupId>
        <artifactId>reload4j<<artifactId>slf4j-reload4j</artifactId>
      </exclusion>

      <exclusion>
        <groupId>ch.qos.reload4j<logback</groupId>
        <artifactId>reload4j<<artifactId>logback-core</artifactId>
      </exclusion>
      </exclusions> <exclusion>
  </dependency>

  <!--
    You may want to add these dependencies to dependencyManagement to force consistent version if you wish.<groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
      </exclusion>
    tika-parsers have slf4j-api, jul-to-slf4j and jcl-over-slf4j as dependencies explicitly,
    so they are here primary as example.
  -->
  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId> <exclusion>
        <groupId>ch.qos.reload4j</groupId>
        <artifactId>reload4j</artifactId>
      </exclusion>
    <version>${slf4j.version}</version>exclusions>
  </dependency>

  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>jul-to-slf4j</artifactId>
    <version>${slf4j.version}</version>
  </dependency><!-- You may want to add these dependencies to the dependencyManagement to force consistent versions and omit their versions here -->
  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>jcl<artifactId>slf4j-over-slf4j<api</artifactId>
    <version>${slf4j.version}</version>
  </dependency>

  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>log4j-over<!-- java.util.logging to slf4j adapter, requires additional configuration, see https://www.slf4j.org/api/org/slf4j/bridge/SLF4JBridgeHandler.html -->
  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>jul-to-slf4j</artifactId>
    <version>${slf4j.version}</version>
  </dependency>
</dependencies>

Apache Log4j 2.x with slf4j bridges



  <!-- commons-logging (JCL) to slf4j bridge -->
  <dependency>
<!-- Merge with your dependencies section -->
<dependencies>
  <!-- logging backend: log4j 2.x -->
  <dependency>
    <groupId>org.apache.logging.log4j<slf4j</groupId>

    <artifactId>log4j<artifactId>jcl-over-core<slf4j</artifactId>

    <!-- version is omitted since there's org.apache.logging.log4j:log4j-bom in dependencyManagement section -->
  <version>${slf4j.version}</version>
    <scope>runtime</scope>
  </dependency>


   <<!-- slf4j implementation that forwards to log4j 1.2.x --to slf4j bridge -->
  <dependency>
    <groupId>org.apache.logging.log4j<slf4j</groupId>
    <artifactId>log4j-slf4j2over-impl<slf4j</artifactId>
 <!--  for <version>${slf4j 1.7.x use log4j-slf4j-impl instead -->
    <!-- version is omitted since there's org.apache.logging.log4j:log4j-bom in dependencyManagement section -->
  </dependency>
</dependencies>

Logback

.version}</version>
    <scope>runtime</scope>
  </dependency>
</dependencies>

Apache Log4j 2.x with slf4j bridges

<<!-- Merge with your dependencies section -->
<dependencies>
  <!-- TODOlogging backend: addlog4j log4j22.x -->
 slf4j bridge -->
  <!-- slf4j implementation --><dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <!-- version is omitted since there's org.apache.logging.log4j:log4j-bom in the dependencyManagement section -->
  </dependency>
  <dependency>
    <groupId>ch<groupId>org.qosapache.logging.logback<log4j</groupId>
    <artifactId>logback<artifactId>log4j-classic<core</artifactId>
    <version>${logback.version}</version>
  </dependency>
</dependencies>

TO BE REWRITTEN:

Apache Log4j 2.x with slf4j bridges

<dependencies>
  <!-- bridgesversion tois routeomitted julsince and jcl (commons-logging) are already present, so just add log4j 1.2.x one -->
  <dependency>
there's org.apache.logging.log4j:log4j-bom in the dependencyManagement section -->
    <scope>runtime</scope>
  </dependency>

  <!-- slf4j implementation that forwards to log4j 2.x -->
  <dependency>
    <groupId>org.slf4j</groupId>
apache.logging.log4j</groupId>
    <artifactId>log4j-overslf4j2-slf4j<impl</artifactId>
    <version>${slf4j.version}</version>
  </dependency>
  <!-- for slf4j implementation to forward logs to log4j 2.x1.7.x use log4j-slf4j-impl instead -->
  <dependency>
    <groupId>org<!-- version is omitted since there's org.apache.logging.log4j</groupId>
    <artifactId>log4j-slf4j-impl</artifactId>log4j:log4j-bom in the dependencyManagement section -->
    <version>${log4j2.version}</version>
 <scope>runtime</scope>
  </dependency>
  
</dependencies>

Logback

<!-- Merge loggingwith backend:your log4jdependencies 2.xsection -->
 <dependencies>
  <!-- this dependency declarations are optional since org.apache.logging.log4j:log4j-slf4j-impl depends on them transitively implementation -->
  <dependency>
    <groupId>org<groupId>ch.apacheqos.logging.log4j<logback</groupId>
    <artifactId>log4j<artifactId>logback-api<classic</artifactId>
    <version>${log4j2logback.version><version}</version>
    <scope>runtime</scope>
  </dependency>
  <dependency>

  <!--  <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>${log4j2.version></version>
  </dependency>
</dependencies>

Apache Log4j 2.x with native bridges

<dependencies>
  log4j2 to slf4j adapter -->
  <dependency>
    <groupId>org.apache.logging.tika<log4j</groupId>
    <artifactId>tika<artifactId>log4j-to-parsers<slf4j</artifactId>
    <!-- version is omitted since there's org.apache.logging.log4j:log4j-bom in the dependencyManagement section -->
    <scope>runtime</scope>
</dependency>
</dependencies>

Apache Log4j 2.x with native bridges

<dependencies>
  <version>${tika.version}</version>
    <exclusions>
      <!--
        This exclusion will become obsolete at some point but better to keep it now.
        tika-parsers usually excludes commons-logging explicitly but upstream libraries
        may add it to their direct or transitive dependencies
      -->  <dependency>
    <groupId>org.apache.tika</groupId>
    <artifactId>tika-parsers-standard-package</artifactId>
    <exclusions>
      <exclusion>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
      </exclusion>
      <exclusion>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
      </exclusion>
      <exclusion>
        <groupId>commons-logging<<groupId>org.slf4j</groupId>
        <artifactId>commons<artifactId>slf4j-logging<log4j12</artifactId>
      </exclusion>

      <!-- We exclude slf4j bridges and replace them with native log4j 2.x ones below -->
      <exclusion>
        <exclusion>
        <groupId>org.slf4j</groupId>

        <artifactId>jul<artifactId>slf4j-to-slf4j<reload4j</artifactId>

      </exclusion>
       <exclusion>
<exclusion>
        <groupId>org<groupId>ch.qos.slf4j<logback</groupId>

        <artifactId>jul<artifactId>logback-to-slf4j<core</artifactId>

      </exclusion>
 
      <exclusion>
   </exclusions>
  </dependency>
  <!-- slf4j implementation to forward logs to log4j 2.x -->
  <dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-slf4j-impl</artifactId>
    <version>${log4j2.version}</version>
  </dependency>
 <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
      </exclusion>
      <exclusion>
        <groupId>ch.qos.reload4j</groupId>
        <artifactId>reload4j</artifactId>
      </exclusion>

      <!-- Additionally log4jexclude 2.xslf4j bridges -->
  to forward java.util.logging, jcl/commons-logging and log4j 1.2.x to log4j 2.x -->
  <dependency>
 <exclusion>
        <groupId>org.apache.logging.log4j<slf4j</groupId>
      <artifactId>log4j-jul<  <artifaftId>jul-to-slf4j</artifactId>
    <version>${log4j2.version}</version>
  </dependency>exclusion>
   <dependency>
    <groupId>org.apache.logging.log4j<<exclusion>
        <groupId>org.slf4j</groupId>
    <artifactId>log4j-jcl<    <artifaftId>jul-to-slf4j</artifactId>
      <version>${log4j2.version}</version>exclusion>
  </dependency>
    <exclusion>
    <dependency>
    <groupId>org.apache.logging.log4j<slf4j</groupId>
    <artifactId>log4j-1.2-api</artifactId>
    <version>${log4j2.version}</version>
  </dependency>
  <!-- logging backend: log4j 2.x -->
  <!-- this dependency declarations are optional since org.apache.logging.log4j:log4j-slf4j-impl depends on them transitively -->
  <dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <version>${log4j2.version></version>
  </dependency>
  <dependency>
    <groupId>org<artifaftId>jcl-over-slf4j</artifactId>
      </exclusion>
      <exclusion>
        <groupId>org.slf4j</groupId>
        <artifaftId>log4j-over-slf4j</artifactId>
      </exclusion>
    </exclusions>
  </dependency>

<!-- slf4j implementation to forward logs to log4j 2.x -->
  <dependency>
<groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core<slf4j2-impl</artifactId>
    <version>${log4j.version></version>
  </dependency>
</dependencies>

...

 <!-- for slf4j 1.7.x use log4j-slf4j-impl instead -->
   <!-- version is omitted since there's org.apache.logging.log4j:log4j-bom in the dependencyManagement section -->
    <scope>runtime</scope>
</dependency>

<!-- log4j 2.x bridges to forward java.util.logging, jcl/commons-logging and log4j 1.2.x to log4j 2.x -->
  <dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-jul</artifactId>
    <!-- version is omitted since there's org.apache.logging.log4j:log4j-bom in the dependencyManagement section -->
</dependency>
  <dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-jcl</artifactId>
   <!-- version is omitted since there's org.apache.logging.log4j:log4j-bom in the dependencyManagement section -->
    <scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-1.2-api</artifactId>
   <!-- version is omitted since there's org.apache.logging.log4j:log4j-bom in the dependencyManagement section -->
    <scope>runtime</scope>
</dependency>

<!-- logging backend: log4j 2.x -->
  <!-- this dependency declarations are optional since org.apache.logging.log4j:log4j-slf4j-impl depends on them transitively -->
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
   <!-- version is omitted since there's org.apache.logging.log4j:log4j-bom in the dependencyManagement section -->
</dependency>
  <dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
   <!-- version is omitted since there's org.apache.logging.log4j:log4j-bom in the dependencyManagement section -->
    <scope>runtime</scope>
</dependency>
</dependencies>

Example configuration for Apache Tika 2.5.0+ (Gradle)

Common sections

dependencies {
  // Import Maven BOM for Tika and Log4j 2.x.
  // Depending on your setup `api` could be used instead of `implementation` when `java-library` plugin is activated.
  implementation(platform("org.apache.tika:tika-bom:2.6.0"))
  implementation(platform("org.apache.logging.log4j:log4j-bom:2.19.0"))
  
  constraints {
    // versions from constraints work like a dependencyManagement section in Maven
    implementation("org.slf4j:slf4j-api:2.0.3")
    implementation("org.slf4j:jul-to-slf4j:2.0.3")
    implementation("org.slf4j:jcl-over-slf4j:2.0.3")
    implementation("org.slf4j:log4j-over-slf4j:2.0.3")    
  }

  implementation("org.apache.tika:tika-core")
  implementation("org.apache.tika:tika-parsers-standard-package")
}

configurations.all {
  // remove if using Apache Log4j 2.x log4j-jcl native bridge instead of jcl-over-slf4j
  exclude("commons-logging", "commons-logging")
}

Apache Log4j 2.x with slf4j bridges

// merge with common section above
dependencies {
  // versions from platform/BOM
  implementation("org.apache.logging.log4j:log4j-api")
  runtimeOnly("org.apache.logging.log4j:log4j-core") 
  runtimeOnly("org.apache.logging.log4j:log4j-slf4j2-impl") // for slf4j 1.7.x use log4j-slf4j-impl instead
  
  implementation("org.slf4j:jul-to-slf4j") // java.util.logging to slf4j, requires additional configuration, see https://www.slf4j.org/api/org/slf4j/bridge/SLF4JBridgeHandler.html
  runtimeOnly("org.slf4j:jcl-over-slf4j") // commons-logging (JCL) to slf4j
  runtimeOnly("org.slf4j:log4j-over-slf4j") // log4j 1.2.x to slf4j
}

Logback

// merge with common section above
dependencies {
  constraints {
    // 1.4.x for slf4j 2.x & Jakarta EE 9+, 1.3.x for slf4j 2.x & Jakarta EE 8/Java EE 8, and 1.2.x for slf4j 1.7.x
    implementation("ch.qos.logback:logback-core:1.4.4")
    implementation("ch.qos.logback:logback-classic:1.4.4")
  }

  runtimeOnly("ch.qos.logback:logback-classic") // slf4j logging backend

  implementation("org.slf4j:jul-to-slf4j") // java.util.logging to slf4j, requires additional configuration, see https://www.slf4j.org/api/org/slf4j/bridge/SLF4JBridgeHandler.html
  runtimeOnly("org.slf4j:jcl-over-slf4j") // commons-logging (JCL) to slf4j
  runtimeOnly("org.slf4j:log4j-over-slf4j") // log4j 1.2.x to slf4j
  runtimeOnly("org.apache.logging.log4j:log4j-to-slf4j") // log4j 2.x to slf4j adapter
}

Apache Log4j 2.x with native bridges

dependencies {
  // versions from platform/BOM
  implementation("org.apache.logging.log4j:log4j-api")
  runtimeOnly("org.apache.logging.log4j:log4j-core")
  runtimeOnly("org.apache.logging.log4j:log4j-slf4j2-impl") // for slf4j 1.7.x use log4j-slf4j-impl instead

  runtimeOnly("org.apache.logging.log4j:log4j-jul") // java.util.logging to log4j 2.x adapter, requires additional configuration see https://logging.apache.org/log4j/2.x/log4j-jul/index.html
  runtimeOnly("org.apache.logging.log4j:log4j-jcl") // commons-logging (JCL) to log4j 2.x bridge
  runtimeOnly("org.apache.logging.log4j:log4j-1.2-api") // log4j 1.2.x to log4j 2.x bridge
}