Checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
    "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
    "https://checkstyle.org/dtds/configuration_1_3.dtd">

<!--
Checkstyle 8.44 configuration for Think Java, 2nd Edition.
-->
<module name="Checker">
    <property name="severity" value="warning"/>

    <!-- See https://checkstyle.sourceforge.io/config.html#TreeWalker -->
    <module name="TreeWalker">

        <!-- See https://checkstyle.sourceforge.io/config_annotation.html -->
        <module name="AnnotationLocation"/>
        <module name="AnnotationUseStyle"/>

        <!-- See https://checkstyle.sourceforge.io/config_blocks.html -->
        <module name="AvoidNestedBlocks"/>
        <module name="EmptyBlock"/>
        <module name="EmptyCatchBlock"/>
        <module name="LeftCurly"/>
        <module name="NeedBraces"/>
        <module name="RightCurly"/>

        <!-- See https://checkstyle.sourceforge.io/config_design.html -->
        <module name="VisibilityModifier">
            <property name="protectedAllowed" value="true"/>
        </module>

        <!-- See https://checkstyle.sourceforge.io/config_coding.html -->
        <module name="AvoidDoubleBraceInitialization"/>
        <module name="AvoidInlineConditionals"/>
        <module name="AvoidNoArgumentSuperConstructorCall"/>
        <module name="DeclarationOrder"/>
        <module name="DefaultComesLast"/>
        <module name="EmptyStatement"/>
        <module name="FallThrough"/>
        <module name="InnerAssignment"/>
        <module name="ModifiedControlVariable"/>
        <module name="MultipleVariableDeclarations"/>
        <module name="OneStatementPerLine"/>
        <module name="ParameterAssignment"/>
        <module name="RequireThis"/>
        <module name="ReturnCount">
            <property name="format" value="^$"/>
        </module>
        <module name="SimplifyBooleanExpression"/>
        <module name="SimplifyBooleanReturn"/>
        <module name="StringLiteralEquality"/>
        <module name="UnnecessaryParentheses"/>

        <!-- See https://checkstyle.sourceforge.io/config_imports.html -->
        <module name="AvoidStarImport">
            <property name="excludes" value="org.junit.jupiter.api.Assertions,org.junit.Assert"/>
        </module>
        <module name="AvoidStaticImport">
            <property name="excludes" value="org.junit.jupiter.api.Assertions.*,org.junit.Assert.*"/>
        </module>
        <module name="IllegalImport"/>
        <module name="RedundantImport"/>
        <module name="UnusedImports"/>

        <!-- See https://checkstyle.sourceforge.io/config_javadoc.html -->
        <module name="AtclauseOrder"/>
        <module name="InvalidJavadocPosition"/>
        <module name="JavadocBlockTagLocation"/>
        <module name="JavadocContentLocation"/>
        <module name="JavadocMethod"/>
        <module name="JavadocMissingWhitespaceAfterAsterisk"/>
        <module name="JavadocStyle"/>
        <module name="JavadocType">
           <property name="authorFormat" value="\S"/>
           <property name="versionFormat" value="\S"/>
        </module>
        <module name="MissingJavadocMethod">
            <property name="scope" value="private"/>
            <property name="allowMissingPropertyJavadoc" value="true"/>
        </module>
        <module name="MissingJavadocType">
            <property name="scope" value="private"/>
        </module>
        <module name="NonEmptyAtclauseDescription"/>
        <module name="RequireEmptyLineBeforeBlockTagGroup"/>
        <module name="SummaryJavadocCheck"/>

        <!-- See https://checkstyle.sourceforge.io/config_misc.html -->
        <module name="ArrayTypeStyle"/>
        <module name="CommentsIndentation"/>
        <module name="Indentation">
            <property name="basicOffset" value="4"/>
            <property name="braceAdjustment" value="0"/>
            <property name="caseIndent" value="4"/>
            <property name="throwsIndent" value="4"/>
            <property name="arrayInitIndent" value="8"/>
            <property name="lineWrappingIndentation" value="4"/>
        </module>
        <property name="tabWidth" value="4"/>
        <module name="OuterTypeFilename"/>
        <module name="UpperEll"/>

        <!-- See https://checkstyle.sourceforge.io/config_modifiers.html -->
        <module name="ModifierOrder"/>
        <module name="RedundantModifier"/>

        <!-- See https://checkstyle.sourceforge.io/config_naming.html -->
        <module name="CatchParameterName"/>
        <module name="ConstantName"/>
        <module name="LocalFinalVariableName">
            <property name="format" value="^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$"/>
        </module>
        <module name="LocalVariableName"/>
        <module name="MemberName"/>
        <module name="MethodName"/>
        <module name="PackageName"/>
        <module name="ParameterName"/>
        <module name="StaticVariableName"/>
        <module name="TypeName"/>

        <!-- See https://checkstyle.sourceforge.io/config_regexp.html -->
        <module name="Regexp">
            <property name="format" value=" //[^ ]"/>
            <property name="illegalPattern" value="true"/>
            <message key="illegal.regexp" value="missing space after ''//'' in comment."/>
        </module>

        <!-- See https://checkstyle.sourceforge.io/config_sizes.html -->
        <module name="MethodLength"/>

        <!-- See https://checkstyle.sourceforge.io/config_whitespace.html -->
        <module name="EmptyLineSeparator">
            <property name="allowNoEmptyLineBetweenFields" value="true"/>
        </module>
        <module name="GenericWhitespace"/>
        <module name="MethodParamPad"/>
        <module name="NoWhitespaceAfter"/>
        <module name="NoWhitespaceBefore"/>
        <module name="OperatorWrap"/>
        <module name="ParenPad"/>
        <module name="SeparatorWrap"/>
        <module name="TypecastParenPad"/>
        <module name="WhitespaceAfter"/>
        <module name="WhitespaceAround"/>

    </module>

    <!-- See https://checkstyle.sourceforge.io/config_sizes.html -->
    <module name="FileLength"/>
    <module name="LineLength"/>

    <!-- See https://checkstyle.sourceforge.io/config_whitespace.html -->
    <module name="FileTabCharacter"/>

</module>