checkstyle-configuration.xml

<?xml version="1.0" encoding="UTF-8"?>
<!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"/>

    <property name="severity" value="error"/>

    <!-- See https://checkstyle.org/config_misc.html#NewlineAtEndOfFile -->
    <module name="NewlineAtEndOfFile"/>

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

    <module name="TreeWalker">
        <property name="tabWidth" value="4"/>

        <!-- Block Checks -->
        <!-- See https://checkstyle.org/config_blocks.html-->
        <module name="LeftCurly">
            <property name="option" value="nl"/>
            <property name="tokens" value="ANNOTATION_DEF,CLASS_DEF,CTOR_DEF,ENUM_CONSTANT_DEF,ENUM_DEF,INTERFACE_DEF,LITERAL_CASE,LITERAL_CATCH,LITERAL_DEFAULT,LITERAL_DO,LITERAL_ELSE,LITERAL_FINALLY,LITERAL_FOR,LITERAL_IF,LITERAL_SWITCH,LITERAL_SYNCHRONIZED,LITERAL_TRY,LITERAL_WHILE,METHOD_DEF,OBJBLOCK,STATIC_INIT,RECORD_DEF,COMPACT_CTOR_DEF"/>
        </module>
        <module name="LeftCurly">
            <property name="option" value="eol"/>
            <property name="tokens" value="LAMBDA"/>
        </module>
        <module name="RightCurly">
            <property name="option" value="alone"/>
        </module>

        <!-- Checks for Coding. -->
        <!-- See https://checkstyle.org/config_coding.html -->
        <module name="DeclarationOrder"/>
        <module name="DefaultComesLast"/>
        <module name="EmptyStatement"/>
        <module name="EqualsHashCode"/>
        <module name="FallThrough"/>
        <module name="HiddenField">
            <property name="ignoreSetter" value="true"/>
            <property name="ignoreConstructorParameter" value="true"/>
        </module>
        <module name="IllegalInstantiation"/>
        <module name="IllegalThrows"/>
        <module name="InnerAssignment"/>
        <!-- <module name="MagicNumber"/> -->
        <module name="MissingSwitchDefault"/>
        <module name="OneStatementPerLine"/>
        <module name="PackageDeclaration"/>
        <module name="ParameterAssignment"/>
        <module name="RequireThis">
            <property name="validateOnlyOverlapping" value="false"/>
        </module>
        <module name="SimplifyBooleanExpression"/>
        <module name="SimplifyBooleanReturn"/>
        <module name="UnnecessaryParentheses"/>

        <!-- Checks for class design -->
        <!-- See https://checkstyle.org/config_design.htm -->
        <module name="FinalClass"/>
        <module name="HideUtilityClassConstructor"/>
        <!-- <module name="InterfaceIsType"/> -->

        <!-- Miscellaneous other checks. -->
        <!-- See https://checkstyle.org/config_misc.htm -->
        <module name="ArrayTypeStyle"/>
        <module name="UpperEll"/>


        <!-- Checks for Naming Conventions. -->
        <!-- See https://checkstyle.org/config_naming.html -->
        <module name="ConstantName"/>
        <module name="ClassTypeParameterName">
            <property name="format" value="^[A-Z0-9]+$"/>
        </module>
        <module name="IllegalIdentifierName"/>
        <module name="InterfaceTypeParameterName">
            <property name="format" value="^[A-Z0-9]+$"/>
        </module>
        <module name="LambdaParameterName"/>
        <module name="LocalFinalVariableName"/>
        <module name="LocalVariableName"/>
        <module name="MemberName"/>
        <module name="MethodTypeParameterName">
            <property name="format" value="^[A-Z0-9]+$"/>
        </module>
        <module name="PackageName">
            <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]*)*$"/>
        </module>
        <module name="ParameterName"/>
        <module name="StaticVariableName"/>
        <module name="TypeName"/>

        <!-- Checks for imports. -->
        <!-- See https://checkstyle.org/config_imports.html -->
        <module name="AvoidStarImport">
            <property name="allowStaticMemberImports" value="true"/>
        </module>
        <module name="IllegalImport"/>
        <module name="RedundantImport"/>
        <module name="UnusedImports">
            <property name="processJavadoc" value="false"/>
        </module>

        <!-- Check for whitespace. -->
        <!-- See https://checkstyle.org/config_whitespace.html -->
        <module name="EmptyForInitializerPad"/>
        <module name="EmptyForIteratorPad"/>
        <module name="EmptyLineSeparator">
            <property name="allowNoEmptyLineBetweenFields" value="true"/>
            <property name="allowMultipleEmptyLines" value="false"/>
            <property name="allowMultipleEmptyLinesInsideClassMembers" value="false"/>
        </module>
        <module name="GenericWhitespace"/>
        <module name="MethodParamPad"/>
        <module name="NoLineWrap"/>
        <module name="NoWhitespaceAfter"/>
        <module name="NoWhitespaceBefore">
            <property name="tokens" value="SEMI"/>
            <property name="allowLineBreaks" value="true"/>
        </module>
        <module name="OperatorWrap"/>
        <module name="ParenPad"/>
        <module name="TypecastParenPad"/>
        <module name="WhitespaceAfter"/>
        <module name="WhitespaceAround"/>
    </module>
</module>