<dependency>
  <groupId>org.testfx</groupId>
  <artifactId>testfx-internal-java8</artifactId>
  <version>4.0.8-alpha</version>
</dependency>

implementation 'org.testfx:testfx-internal-java8:4.0.8-alpha'

implementation("org.testfx:testfx-internal-java8:4.0.8-alpha")

libraryDependencies += "org.testfx" % "testfx-internal-java8" % "4.0.8-alpha"

@Grapes(
  @Grab(group='org.testfx', module='testfx-internal-java8', version='4.0.8-alpha')
)

<dependency org="org.testfx" name="testfx-internal-java8" rev="4.0.8-alpha" />

[org.testfx/testfx-internal-java8 "4.0.8-alpha"]

'org.testfx:testfx-internal-java8:jar:4.0.8-alpha'