checkstyle.xml

<?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">
    <module name="TreeWalker">
        <!-- Set the indentation to 4 spaces -->
        <module name="Indentation">
            <property name="basicOffset" value="4"/>
            <property name="braceAdjustment" value="0"/>
            <property name="caseIndent" value="4"/>
            <property name="throwsIndent" value="4"/>
        </module>
        <!-- Use Intellij import order -->
        <module name="CustomImportOrder">
            <property name="customImportOrderRules"
                      value="THIRD_PARTY_PACKAGE###SPECIAL_IMPORTS###STANDARD_JAVA_PACKAGE###STATIC"/>
            <property name="sortImportsInGroupAlphabetically" value="true"/>
            <property name="standardPackageRegExp" value="^(java|javax)\."/>
            <property name="separateLineBetweenGroups" value="true"/>
        </module>
    </module>
    <!-- Set the line length max to 120 -->
    <module name="LineLength">
        <property name="fileExtensions" value="java"/>
        <property name="max" value="120"/>
        <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
    </module>
</module>