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="charset" value="UTF-8"/>

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

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

    <module name="SuppressWarningsFilter"/>
    
    <module name="FileTabCharacter">
        <property name="eachLine" value="true"/>
    </module>

    <module name="FileLength">
        <property name="max" value="1500"/>
    </module>

    <module name="TreeWalker">
       <module name="SuppressWarningsHolder" />
        
        <module name="OuterTypeFilename"/>
        <module name="IllegalTokenText">
            <property name="tokens" value="STRING_LITERAL, CHAR_LITERAL"/>
            <property name="format" value="\\u00(09|0(a|A)|0(c|C)|0(d|D)|22|27|5(C|c))|\\(0(10|11|12|14|15|42|47)|134)"/>
            <property name="message" value="Consider using special escape sequence instead of octal value or Unicode escaped value."/>
        </module>
        <module name="AvoidEscapedUnicodeCharacters">
            <property name="allowEscapesForControlCharacters" value="true"/>
            <property name="allowByTailComment" value="true"/>
            <property name="allowNonPrintableEscapes" value="true"/>
        </module>
        <module name="LineLength">
            <property name="max" value="120"/>
            <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
        </module>
        <module name="OneTopLevelClass"/>
        <module name="NoLineWrap"/>
        <module name="EmptyBlock">
            <property name="option" value="TEXT"/>
            <property name="tokens"
             value="LITERAL_TRY, LITERAL_FINALLY, LITERAL_CATCH, LITERAL_IF, LITERAL_ELSE, LITERAL_SWITCH, STATIC_INIT"/>
        </module>
        <module name="NeedBraces"/>
        <module name="LeftCurly"/>
        <module name="RightCurly">
            <property name="id" value="RightCurlySame"/>
            <property name="tokens"
             value="LITERAL_TRY, LITERAL_CATCH, LITERAL_FINALLY, LITERAL_IF, LITERAL_ELSE,
                    LITERAL_DO"/>
        </module>
        <module name="RightCurly">
            <property name="id" value="RightCurlyAlone"/>
            <property name="option" value="alone"/>
            <property name="tokens"
             value="CLASS_DEF, METHOD_DEF, CTOR_DEF, LITERAL_FOR, LITERAL_WHILE, STATIC_INIT,
                    INSTANCE_INIT"/>
        </module>
        <module name="WhitespaceAround">
            <property name="allowEmptyConstructors" value="false"/>
            <property name="allowEmptyMethods" value="false"/>
            <property name="allowEmptyTypes" value="true"/>
            <property name="allowEmptyLoops" value="true"/>
            <property name="allowEmptyLambdas" value="true"/>
            <message key="ws.notFollowed" value="WhitespaceAround: ''{0}'' is not followed by whitespace. Empty blocks may only be represented as '{}' when not part of a multi-block statement (4.1.3)"/>
            <message key="ws.notPreceded" value="WhitespaceAround: ''{0}'' is not preceded with whitespace."/>
        </module>
        <module name="OneStatementPerLine"/>
        <module name="MultipleVariableDeclarations"/>
        <module name="ArrayTypeStyle"/>
        <module name="DeclarationOrder">
            <property name="ignoreConstructors" value="true"/>
        </module>
        <module name="MissingSwitchDefault"/>
        <module name="FallThrough"/>
        <module name="UpperEll"/>
        <module name="ModifierOrder"/>
        <module name="EmptyLineSeparator">
            <property name="allowNoEmptyLineBetweenFields" value="true"/>
            <property name="allowMultipleEmptyLines" value="false"/>
            <property name="allowMultipleEmptyLinesInsideClassMembers" value="false"/>
            <property name="tokens" value="PACKAGE_DEF, IMPORT, STATIC_IMPORT, CLASS_DEF, INTERFACE_DEF, ENUM_DEF, STATIC_INIT, INSTANCE_INIT, CTOR_DEF, VARIABLE_DEF"/>
        </module>
        <module name="SeparatorWrap">
            <property name="id" value="SeparatorWrapDot"/>
            <property name="tokens" value="DOT"/>
            <property name="option" value="nl"/>
        </module>
        <module name="SeparatorWrap">
            <property name="id" value="SeparatorWrapComma"/>
            <property name="tokens" value="COMMA"/>
            <property name="option" value="EOL"/>
        </module>
        <module name="SeparatorWrap">
            <property name="id" value="SeparatorWrapEllipsis"/>
            <property name="tokens" value="ELLIPSIS"/>
            <property name="option" value="EOL"/>
        </module>
        <module name="SeparatorWrap">
            <property name="id" value="SeparatorWrapArrayDeclarator"/>
            <property name="tokens" value="ARRAY_DECLARATOR"/>
            <property name="option" value="EOL"/>
        </module>
        <module name="SeparatorWrap">
            <property name="id" value="SeparatorWrapMethodRef"/>
            <property name="tokens" value="METHOD_REF"/>
            <property name="option" value="nl"/>
        </module>
        <module name="PackageName">
            <property name="format" value="^[a-z_]+(\.[a-z][a-z0-9_]*)*$"/>
            <message key="name.invalidPattern"
             value="Package name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="TypeName">
            <message key="name.invalidPattern"
             value="Type name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="MemberName">
            <property name="format" value="^[a-z][a-zA-Z0-9]*$"/>
            <message key="name.invalidPattern"
             value="Member name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="ParameterName">
            <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
            <message key="name.invalidPattern"
             value="Parameter name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="LambdaParameterName">
            <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
            <message key="name.invalidPattern"
                     value="Lambda parameter name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="CatchParameterName">
            <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
            <message key="name.invalidPattern"
             value="Catch parameter name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="LocalVariableName">
            <property name="tokens" value="VARIABLE_DEF"/>
            <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
            <property name="allowOneCharVarInForLoop" value="true"/>
            <message key="name.invalidPattern"
             value="Local variable name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="ClassTypeParameterName">
            <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
            <message key="name.invalidPattern"
             value="Class type name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="MethodTypeParameterName">
            <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
            <message key="name.invalidPattern"
             value="Method type name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="InterfaceTypeParameterName">
            <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
            <message key="name.invalidPattern"
             value="Interface type name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="GenericWhitespace">
            <message key="ws.followed"
             value="GenericWhitespace ''{0}'' is followed by whitespace."/>
            <message key="ws.preceded"
             value="GenericWhitespace ''{0}'' is preceded with whitespace."/>
            <message key="ws.illegalFollow"
             value="GenericWhitespace ''{0}'' should followed by whitespace."/>
            <message key="ws.notPreceded"
             value="GenericWhitespace ''{0}'' is not preceded with whitespace."/>
        </module>
        <module name="AbbreviationAsWordInName">
            <property name="allowedAbbreviations" value="false"/>
        </module>
        <module name="MethodParamPad"/>
        <module name="NoWhitespaceBefore">
            <property name="tokens"
             value="COMMA, SEMI, POST_INC, POST_DEC, DOT, ELLIPSIS, METHOD_REF"/>
            <property name="allowLineBreaks" value="true"/>
        </module>
        <module name="ParenPad"/>
        <module name="AnnotationLocation">
            <property name="id" value="AnnotationLocationMostCases"/>
            <property name="tokens"
             value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF"/>
        </module>
        <module name="AnnotationLocation">
            <property name="id" value="AnnotationLocationVariables"/>
            <property name="tokens" value="VARIABLE_DEF"/>
            <property name="allowSamelineMultipleAnnotations" value="false"/>
        </module>
        <module name="NonEmptyAtclauseDescription"/>
        <module name="SummaryJavadoc">
            <property name="forbiddenSummaryFragments"
             value="^@return the *|^This method returns |^A [{]@code [a-zA-Z0-9]+[}]( is a )"/>
        </module>
        <module name="JavadocParagraph"/>
        <module name="AtclauseOrder">
            <property name="tagOrder" value="@param, @return, @throws, @deprecated"/>
            <property name="target"
             value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF, VARIABLE_DEF"/>
        </module>
        <module name="JavadocMethod">
            <property name="scope" value="public"/>
            <property name="allowMissingParamTags" value="true"/>
            <property name="allowMissingThrowsTags" value="true"/>
            <property name="allowMissingReturnTag" value="true"/>
            <property name="minLineCount" value="2"/>
            <property name="allowedAnnotations" value="Override, Test"/>
            <property name="allowThrowsTagsForSubclasses" value="true"/>
            <property name="allowMissingJavadoc" value="true"/>
        </module>
        <module name="MethodName">
            <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9_]*$"/>
            <message key="name.invalidPattern"
             value="Method name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="SingleLineJavadoc">
            <property name="ignoreInlineTags" value="false"/>
        </module>
        <module name="EmptyCatchBlock">
            <property name="exceptionVariableName" value="expected"/>
        </module>
        <module name="CommentsIndentation"/>

        <module name="AvoidNestedBlocks"/> 
        <module name="DefaultComesLast"/>
        <module name="EqualsHashCode"/>
        <module name="HiddenField">
            <property name="ignoreConstructorParameter" value="true"/>
            <property name="ignoreSetter" value="true"/>
        </module>
        <module name="InnerTypeLast"/>
        <module name="MagicNumber"/>
        <module name="MethodLength">
            <property name="max" value="150"/>
        </module>
        <module name="ModifiedControlVariable"/>
        <module name="MutableException"/>
        <module name="NestedForDepth"/>
        <module name="NestedIfDepth">
            <property name="max" value="2"/>
        </module>
        <module name="NestedTryDepth">
            <property name="max" value="2"/>
        </module>
        <module name="NoFinalizer"/>
        <module name="NoClone"/>       
        <module name="PackageDeclaration"/>
        <module name="ParameterAssignment"/>
        <module name="RedundantImport"/>
        <module name="RedundantModifier"/>
        <module name="RequireThis">
            <property name="checkFields" value="true"/>
            <property name="checkMethods" value="true"/>
            <property name="validateOnlyOverlapping" value="true"/>
        </module>
        <module name="SingleSpaceSeparator"/>
        <module name="StringLiteralEquality"/>
        <module name="TodoComment">
            <property name="format" value="FIXME"/>
        </module>
        <module name="UnnecessaryParentheses">
            <property name="tokens" value="EXPR, IDENT, NUM_DOUBLE, NUM_FLOAT, NUM_INT, NUM_LONG, STRING_LITERAL, LITERAL_NULL, 
                LITERAL_FALSE, LITERAL_TRUE, ASSIGN, BAND_ASSIGN, BOR_ASSIGN, BSR_ASSIGN, BXOR_ASSIGN, DIV_ASSIGN, MINUS_ASSIGN, 
                MOD_ASSIGN, PLUS_ASSIGN, SL_ASSIGN, SR_ASSIGN, STAR_ASSIGN"/>
        </module>
        <module name="UnusedImports"/>
        <module name="VisibilityModifier">
            <property name="protectedAllowed" value="true"/>
        </module>
        <module name="WhitespaceAfter"/>

        <!-- From com.github.sevntu -->

        <module name="AvoidConditionInversion"/>
        <module name="AvoidHidingCauseException"/>
        <module name="CauseParameterInException"/>
        <module name="DiamondOperatorForVariableDefinition"/>
        <module name="EitherLogOrThrow"/>
        <module name="MapIterationInForEachLoop"/>
        <module name="UselessSuperCtorCall"/>
        <module name="UselessSingleCatch"/>
        <module name="UniformEnumConstantName"/>
        <module name="TernaryPerExpressionCount"/>
        <module name="SimpleAccessorNameNotation"/>
        <module name="ReturnBooleanFromTernary"/>
        <module name="NoNullForCollectionReturn"/>
        <module name="NestedSwitch"/>

    </module>
</module>