checkstyle.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="fileExtensions" value="java, xml" />

    <module name="FileLength" />
    <module name="FileTabCharacter" />

    <module name="NewlineAtEndOfFile">
        <property name="fileExtensions" value="java" />
    </module>

    <!-- Blank lines count -->
    <module name="RegexpMultiline">
        <property name="format" value="(\n\s*){4,}" />
        <property name="message" value="Maximum 2 subsequent blank lines are allowed" />
    </module>

    <!-- Trailing spaces -->
    <module name="RegexpSingleline">
        <property name="format" value="\s+$" />
        <property name="message" value="Line has trailing spaces." />
    </module>

    <!-- For each spacing -->
    <module name="RegexpSingleline">
        <property name="format" value="^\s*for \(.*?([^ ]:|:[^ ])" />
        <property name="message" value="Space needed around ':' character." />
    </module>

    <module name="SuppressWarningsFilter" />

    <module name="LineLength">
        <property name="max" value="100" />
        <property name="fileExtensions" value="java" />
    </module>

    <module name="TreeWalker">

        <!-- Checks for annotations.                             -->
        <!-- See http://checkstyle.sf.net/config_annotation.html -->
        <module name="AnnotationLocation">
            <property name="tokens"
                value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF" />
        </module>
        <module name="AnnotationLocation">
            <property name="tokens" value="VARIABLE_DEF" />
            <property name="allowSamelineMultipleAnnotations" value="true" />
        </module>
        <module name="MissingDeprecated" />
        <module name="MissingOverride" />
        <module name="SuppressWarningsHolder" />


        <!-- Checks for blocks.                              -->
        <!-- See http://checkstyle.sf.net/config_blocks.html -->
        <module name="EmptyBlock">
            <property name="option" value="TEXT" />
            <property name="tokens"
                value="LITERAL_TRY, LITERAL_FINALLY, LITERAL_IF, LITERAL_ELSE, LITERAL_SWITCH" />
        </module>
        <module name="EmptyCatchBlock">
            <property name="exceptionVariableName" value="ignored" />
        </module>
        <module name="LeftCurly" />
        <module name="NeedBraces" />
        <module name="RightCurly" />
        <module name="RightCurly">
            <property name="option" value="alone" />
            <property name="tokens" value="CLASS_DEF, METHOD_DEF, LITERAL_FOR, LITERAL_WHILE,
                LITERAL_DO, STATIC_INIT, INSTANCE_INIT" />
        </module>


        <!-- Checks for class design.                        -->
        <!-- See http://checkstyle.sf.net/config_design.html -->
        <module name="HideUtilityClassConstructor" />
        <module name="InnerTypeLast" />
        <module name="InterfaceIsType" />
        <module name="OneTopLevelClass" />


        <!-- Checks for common coding problems.              -->
        <!-- See http://checkstyle.sf.net/config_coding.html -->
        <module name="CovariantEquals" />
        <module name="EmptyStatement" />
        <module name="EqualsHashCode" />
        <module name="FallThrough" />
        <module name="IllegalInstantiation" />
        <module name="MissingSwitchDefault" />
        <module name="MultipleVariableDeclarations" />
        <module name="NoFinalizer" />
        <module name="OneStatementPerLine" />
        <module name="OverloadMethodsDeclarationOrder" />
        <module name="SimplifyBooleanExpression" />
        <module name="SimplifyBooleanReturn" />
        <module name="VariableDeclarationUsageDistance" />


        <!-- Checks for imports.                             -->
        <!-- See http://checkstyle.sf.net/config_import.html -->
        <module name="AvoidStarImport" />
        <module name="ImportOrder">
            <property name="groups" value="android,androidx,com,junit,net,org,java,javax" />
            <property name="ordered" value="true" />
            <property name="separated" value="true" />
            <property name="option" value="bottom" />
        </module>
        <module name="IllegalImport" />
        <module name="RedundantImport" />
        <module name="UnusedImports" />


        <!-- Checks for javadoc comments.                     -->
        <!-- See http://checkstyle.sf.net/config_javadoc.html -->
        <module name="JavadocStyle" />
        <module name="NonEmptyAtclauseDescription" />


        <!-- Checks for modifiers.                              -->
        <!-- See http://checkstyle.sf.net/config_modifiers.html -->
        <module name="ModifierOrder" />
        <module name="RedundantModifier" />


        <!-- Checks for naming conventions.                  -->
        <!-- See http://checkstyle.sf.net/config_naming.html -->
        <module name="AbbreviationAsWordInName">
            <property name="ignoreFinal" value="false" />
            <property name="allowedAbbreviationLength" value="1" />
        </module>
        <module name="LocalVariableName">
            <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9]*$" />
            <property name="allowOneCharVarInForLoop" value="true" />
        </module>
        <module name="MemberName">
            <property name="format" value="^([a-z][a-z0-9][a-zA-Z0-9]*)|x|y$" />
        </module>
        <module name="MethodName">
            <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9_]*$" />
        </module>
        <module name="PackageName">
            <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]*)*$" />
        </module>
        <module name="ParameterName">
            <property name="format" value="^([a-z][a-z0-9][a-zA-Z0-9]*)|x|y$" />
        </module>
        <module name="StaticVariableName">
            <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9]*$" />
        </module>
        <module name="TypeName" />

        <module name="MethodLength" />

        <!-- Checks for whitespace.                              -->
        <!-- See http://checkstyle.sf.net/config_whitespace.html -->
        <module name="EmptyLineSeparator">
            <property name="allowNoEmptyLineBetweenFields" value="true" />
        </module>
        <module name="GenericWhitespace" />
        <module name="MethodParamPad" />
        <module name="NoLineWrap" />
        <module name="NoWhitespaceAfter">
            <property name="tokens" value="BNOT, DEC, DOT, INC, LNOT, UNARY_MINUS, UNARY_PLUS" />
        </module>
        <module name="NoWhitespaceBefore" />
        <module name="OperatorWrap" />
        <module name="ParenPad" />
        <module name="TypecastParenPad" />
        <module name="WhitespaceAfter" />
        <module name="WhitespaceAround">
            <property name="allowEmptyConstructors" value="true" />
            <property name="allowEmptyMethods" value="true" />
            <property name="allowEmptyTypes" value="true" />
            <property name="allowEmptyLoops" value="true" />
        </module>


        <!-- Miscellaneous checks.                         -->
        <!-- See http://checkstyle.sf.net/config_misc.html -->
        <module name="ArrayTypeStyle" />
        <module name="AvoidEscapedUnicodeCharacters">
            <property name="allowEscapesForControlCharacters" value="true" />
            <property name="allowByTailComment" value="true" />
            <property name="allowNonPrintableEscapes" value="true" />
        </module>
        <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="8" />
            <property name="lineWrappingIndentation" value="8" />
            <property name="arrayInitIndent" value="4" />
        </module>
        <module name="OuterTypeFilename" />
        <module name="UpperEll" />

    </module>

</module>