checkstyle.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE module PUBLIC "-//Puppy Crawl//DTD Check Configuration 1.2//EN" "http://www.puppycrawl.com/dtds/configuration_1_2.dtd">
<module name="Checker">
    <module name="FileTabCharacter" />
    <module name="NewlineAtEndOfFile" />
    <module name="RegexpSingleline">
        <property name="format" value="\s+$"/>
        <property name="message" value="Trailing spaces are not allowed."/>
    </module>
    <module name="TreeWalker">
        <module name="ImportOrder">
            <property name="groups" value="*,com,edu,hudson,io,java,javax,jenkins,net,okhttp3,org.apache,org.jenkinsci,org.jvnet.hudson,org.junit,org.kohsuke,org.pircbotx,org" />
            <property name="ordered" value="true"/>
            <property name="separated" value="true"/>
            <property name="option" value="bottom"/>
            <property name="sortStaticImportsAlphabetically" value="true"/>
            <!-- See also https://github.com/checkstyle/checkstyle/issues/5476
                 and https://github.com/checkstyle/checkstyle/issues/7425
              -->
        </module>
        <module name="UnusedImports" />
    </module>
</module>