If you want to migrate from existing log4j 1.x in your project to log4j 2.x then remove all existing log4j 1.x dependencies and add the following dependency:

Log4j 1.x API Bridge

Maven Build

<dependencies>
  <dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-1.2-api</artifactId>
    <version>2.6.2</version>
  </dependency>
</dependencies>

Ivy Build

<dependencies>
  <dependency org="org.apache.logging.log4j" name="log4j-1.2-api" rev="2.6.2" />
</dependencies>

Gradle Build

dependencies {
  compile group: 'org.apache.logging.log4j', name: 'log4j-1.2-api', version: '2.6.2'
}

Apache Commons Logging Bridge If your project is using Apache Commons Logging which use log4j 1.x and you want to migrate it to log4j 2.x then add the following dependencies:

Maven Build

<dependencies>
  <dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-jcl</artifactId>
    <version>2.6.2</version>
  </dependency>
</dependencies>

Ivy Build

<dependencies>
  <dependency org="org.apache.logging.log4j" name="log4j-jcl" rev="2.6.2" />
</dependencies>

Gradle Build

dependencies {
  compile group: 'org.apache.logging.log4j', name: 'log4j-jcl', version: '2.6.2'
}

Note: Do not remove any existing dependencies of Apache commons logging

Reference: https://logging.apache.org/log4j/2.x/maven-artifacts.html