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

    <property name="fileExtensions" value="java, properties, xml"/>

    <module name="BeforeExecutionExclusionFileFilter">
        <property name="fileNamePattern" value="module\-info\.java$"/>
    </module>

    <!-- https://checkstyle.org/config_filters.html#SuppressionFilter -->
    <module name="SuppressionFilter">
        <property name="file" value="${org.checkstyle.sun.suppressionfilter.config}" default="checkstyle-suppressions.xml" />
        <property name="optional" value="true"/>
    </module>

    <module name="SuppressWarningsFilter" />

    <!-- Checks whether files end with a new line. -->
    <!-- See https://checkstyle.org/config_misc.html#NewlineAtEndOfFile -->
    <module name="NewlineAtEndOfFile"/>

    <!-- Checks that property files contain the same keys. -->
    <!-- See https://checkstyle.org/config_misc.html#Translation -->
    <module name="Translation"/>

    <!-- Checks for Size Violations. -->
    <!-- See https://checkstyle.org/config_sizes.html -->
    <module name="FileLength">
        <property name="max" value="600"/>
    </module>
    <module name="LineLength">
        <property name="fileExtensions" value="java"/>
        <property name="max" value="250"/>
        <property name="ignorePattern" value="^ *\* .*$"/>
    </module>

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

    <module name="TreeWalker">
        <!-- Checks for Javadoc comments.                     -->
        <!-- See https://checkstyle.org/config_javadoc.html -->
        <!--
        <module fullName="InvalidJavadocPosition"/>
        <module fullName="JavadocMethod"/>
        <module fullName="JavadocType"/>
        <module fullName="JavadocVariable"/>
        <module fullName="JavadocStyle"/>
        <module fullName="MissingJavadocMethod"/>
        -->

        <!-- Checks for Naming Conventions.                  -->
        <!-- See https://checkstyle.org/config_naming.html -->
        <module name="IllegalIdentifierName"/>
        <module name="LocalVariableName"/>
        <module name="MemberName"/>
        <module name="MethodName"/>
        <module name="PackageName"/>
        <module name="ParameterName"/>
        <module name="StaticVariableName"/>
        <module name="TypeName"/>

        <!-- Checks for imports                              -->
        <!-- See https://checkstyle.org/config_imports.html -->
        <module name="IllegalImport"/> <!-- defaults to sun.* packages -->
        <module name="RedundantImport"/>
        <module name="UnusedImports">
            <property name="processJavadoc" value="false"/>
        </module>

        <!-- Checks for Size Violations.                    -->
        <!-- See https://checkstyle.org/config_sizes.html -->
        <module name="MethodLength">
            <property name="max" value="120"/>
        </module>
        <module name="ParameterNumber"/>

        <!-- Checks for whitespace                               -->
        <!-- See https://checkstyle.org/config_whitespace.html -->
        <module name="EmptyLineSeparator">
            <property name="allowNoEmptyLineBetweenFields" value="true"/>
        </module>
        <module name="GenericWhitespace"/>
        <module name="MethodParamPad"/>
        <module name="NoWhitespaceAfter"/>
        <!-- <module fullName="NoWhitespaceBefore"/> -->
        <module name="OperatorWrap"/>
        <module name="ParenPad"/>
        <module name="TypecastParenPad"/>
        <module name="WhitespaceAfter"/>

        <!-- Modifier Checks                                    -->
        <!-- See https://checkstyle.org/config_modifier.html -->
        <module name="ModifierOrder"/>
        <module name="RedundantModifier"/>

        <!-- Checks for blocks. You know, those {}'s         -->
        <!-- See https://checkstyle.org/config_blocks.html -->
        <module name="AvoidNestedBlocks"/>
        <module name="EmptyBlock"/>
        <module name="LeftCurly">
            <property name="option" value="eol"/>
            <property name="tokens" value="LAMBDA"/>
            <property name="tokens" value="LITERAL_CASE"/>
            <property name="tokens" value="LITERAL_CATCH"/>
            <property name="tokens" value="LITERAL_DO"/>
            <property name="tokens" value="LITERAL_ELSE"/>
            <property name="tokens" value="LITERAL_FINALLY"/>
        </module>
        <module name="LeftCurly">
            <property name="option" value="nl"/>
            <property name="tokens" value="ANNOTATION_DEF"/>
            <property name="tokens" value="CLASS_DEF"/>
            <property name="tokens" value="INTERFACE_DEF"/>
            <!-- <property fullName="tokens" value="CTOR_DEF"/> -->
            <property name="tokens" value="ENUM_CONSTANT_DEF"/>
            <property name="tokens" value="ENUM_DEF"/>
            <property name="tokens" value="LITERAL_FOR"/>
            <property name="tokens" value="LITERAL_IF"/>
            <property name="tokens" value="LITERAL_WHILE"/>
            <!-- <property fullName="tokens" value="METHOD_DEF"/> -->
        </module>
        <module name="RightCurly">
            <property name="option" value="alone_or_singleline"/>
        </module>

        <!-- Checks for common coding problems               -->
        <!-- See https://checkstyle.org/config_coding.html -->
        <module name="ArrayTrailingComma"/>
        <module name="AvoidNoArgumentSuperConstructorCall"/>
        <module name="CovariantEquals"/>
        <module name="DefaultComesLast"/>
        <module name="EmptyStatement"/>
        <module name="EqualsHashCode"/>
        <module name="FallThrough"/>
        <module name="IllegalCatch"/>
        <module name="IllegalInstantiation"/>
        <module name="IllegalThrows"/>
        <module name="InnerAssignment"/>
        <module name="MissingSwitchDefault"/>
        <module name="MultipleVariableDeclarations"/>
        <module name="NestedForDepth">
            <property name="max" value="2"/>
        </module>
        <module name="NestedIfDepth">
            <property name="max" value="3"/>
        </module>
        <module name="NestedTryDepth">
            <property name="max" value="0"/>
        </module>
        <module name="NoClone"/>
        <module name="NoFinalizer"/>
        <module name="RequireThis"/>
        <module name="SimplifyBooleanReturn"/>
        <module name="StringLiteralEquality"/>

        <!-- Checks for class design -->
        <!-- See https://checkstyle.org/config_design.html -->
        <module name="FinalClass"/>
        <module name="InnerTypeLast"/>
        <module name="MutableException"/>
        <module name="OneTopLevelClass"/>

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

        <module name="SuppressWarningsHolder" />
        <!-- https://checkstyle.org/config_filters.html#SuppressionXpathFilter -->
        <module name="SuppressionXpathFilter">
            <property name="file" value="${org.checkstyle.sun.suppressionxpathfilter.config}"
                      default="checkstyle-xpath-suppressions.xml" />
            <property name="optional" value="true"/>
        </module>
    </module>
</module>