Optional

<dependency>
    <groupId>ant</groupId>
    <artifactId>optional</artifactId>
    <version>1.5.4</version>
</dependency>

compile group: 'ant', name: 'optional', version: '1.5.4'

compile 'ant:optional:1.5.4'

libraryDependencies += "ant" % "optional" % "1.5.4"

<dependency org="ant" name="optional" rev="1.5.4"/>

@Grapes(
            @Grab(group='ant', module='optional', version='1.5.4')
        )

[ant/optional "1.5.4"]

'ant:optional:jar:1.5.4'