<dependency>
  <groupId>log4j</groupId>
  <artifactId>log4j</artifactId>
  <version>1.2.6</version>
</dependency>

implementation 'log4j:log4j:1.2.6'

implementation("log4j:log4j:1.2.6")

libraryDependencies += "log4j" % "log4j" % "1.2.6"

@Grapes(
  @Grab(group='log4j', module='log4j', version='1.2.6')
)

<dependency org="log4j" name="log4j" rev="1.2.6" />

[log4j/log4j "1.2.6"]

'log4j:log4j:jar:1.2.6'