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">
        <module name="UnusedImports" />
    </module>


    <property name="fileExtensions" value="java"/>
    <module name="BeforeExecutionExclusionFileFilter">
        <property name="fileNamePattern" value=".*Test\.java$"/>
    </module>

    <module name="TreeWalker">
        <module name="MissingJavadocMethod">
            <property name="severity" value="warning"/>
            <property name="scope" value="public"/>
            <property name="minLineCount" value="0"/>
            <property name="allowedAnnotations" value="Main"/>
            <property name="tokens" value="METHOD_DEF, CTOR_DEF, COMPACT_CTOR_DEF"/>
        </module>
        <module name="JavadocMethod">
            <property name="accessModifiers" value="public"/>
            <property name="allowMissingParamTags" value="false"/>
            <property name="allowMissingReturnTag" value="false"/>
        </module>
        <module name="MethodLength">
            <property name="severity" value="warning"/>
            <property name="tokens" value="METHOD_DEF, CTOR_DEF, COMPACT_CTOR_DEF"/>
            <property name="max" value="60"/>
        </module>
        <module name="VisibilityModifier">
            <property name="severity" value="warning"/>
            <property name="protectedAllowed" value="true"/>
        </module>

        <module name="OuterTypeFilename">
            <property name="severity" value="warning"/>
        </module>
        <module name="ParameterNumber">
            <property name="severity" value="warning"/>
            <property name="tokens" value="METHOD_DEF, CTOR_DEF"/>
            <property name="max" value="6"/>
        </module>
        <module name="CyclomaticComplexity">
            <property name="severity" value="warning"/>
            <property name="switchBlockAsSingleDecisionPoint" value="true"/>
            <property name="max" value="6"/>
            <property name="tokens" value="LITERAL_WHILE, LITERAL_DO, LITERAL_FOR, LITERAL_IF, LITERAL_SWITCH, LITERAL_CASE, QUESTION"/>
        </module>
        <module name="Indentation">
            <property name="severity" value="warning"/>
        </module>
        <module name="UnusedImports">
            <property name="severity" value="warning"/>
        </module>

        <module name="MemberName">
            <property name="severity" value="warning"/>
        </module>
        <module name="MethodName">
            <property name="severity" value="warning"/>
        </module>
        <module name="ParameterName">
            <property name="severity" value="warning"/>
        </module>
        <module name="LocalVariableName">
            <property name="severity" value="warning"/>
        </module>
        <module name="StaticVariableName">
            <property name="severity" value="warning"/>
        </module>
        <module name="LambdaParameterName">
            <property name="severity" value="warning"/>
        </module>
        <module name="TypeName">
            <property name="severity" value="warning"/>
        </module>
        <module name="ClassTypeParameterName">
            <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*$)"/>
            <message key="name.invalidPattern"
                     value="Class type name ''{0}'' must match pattern ''{1}''."/>
        </module>
    </module>

    <module name="LineLength">
        <property name="severity" value="warning"/>
        <property name="fileExtensions" value="java"/>
        <property name="max" value="100"/>
        <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
    </module>

    <!-- TODO: decide in your team with other checkers to add! -->

</module>