Checkstyle is a development tool to help programmers write Java code that adheres to a coding standard
'checkstyle:checkstyle-optional:4.2'
<dependency>
<groupId>checkstyle</groupId>
<artifactId>checkstyle-optional</artifactId>
<version>4.2</version>
</dependency>
<dependency org="checkstyle" name="checkstyle-optional" rev="4.2"/>
"checkstyle", "checkstyle-optional", "4.2"