<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
        "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
        "https://checkstyle.org/dtds/configuration_1_3.dtd">
<module name="Checker">
    <property name="charset" value="UTF-8"/>
    <module name="NewlineAtEndOfFile">
        <property name="lineSeparator" value="lf"/>
    </module>
    <module name="LineLength">
      <property name="max" value="85"/>
    </module>
    <!-- ... -->
</module>

plugins {
  java
  checkstyle
}

repositories {
  mavenCentral()
}

<root>
└── config
    └── checkstyle           
        └── checkstyle.xml   
        └── suppressions.xml

$ ./gradlew check

> Task :checkstyleMain
[ant:checkstyle] [ERROR] /<PATH-TO-PROJ>/src/main/java/.../File.java:4: 
                         Line is longer than 85 characters (found 102). [LineLength]

> Task :checkstyleMain FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':checkstyleMain'.
> A failure occurred while executing org.gradle.api.plugins.quality.internal.CheckstyleAction
   > Checkstyle rule violations were found. See the report at: file:///<PATH-TO-PROJ>/build/reports/checkstyle/main.html
     Checkstyle files with violations: 1
     Checkstyle violations by severity: [error:1]