<dependency>
  <groupId>org.apache.logging.log4j</groupId>
  <artifactId>log4j</artifactId>
  <version>2.3.1</version>
  <type>pom</type>
</dependency>

implementation 'org.apache.logging.log4j:log4j:2.3.1'

implementation("org.apache.logging.log4j:log4j:2.3.1")

libraryDependencies += "org.apache.logging.log4j" % "log4j" % "2.3.1"

@Grapes(
  @Grab(group='org.apache.logging.log4j', module='log4j', version='2.3.1')
)

<dependency org="org.apache.logging.log4j" name="log4j" rev="2.3.1" />

[org.apache.logging.log4j/log4j "2.3.1"]

'org.apache.logging.log4j:log4j:jar:2.3.1'