etc/checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
        "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
<module name="Checker">
    <property name="charset" value="UTF-8"/>

    <module name="NewlineAtEndOfFile">
        <property name="lineSeparator" value="lf"/>
    </module>

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

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

        <!-- Code -->
        <module name="NoFinalizer"/>
        <module name="ArrayTypeStyle"/>
        <module name="FallThrough"/>
        <module name="OuterTypeFilename"/>
        <module name="UpperEll"/>
        <module name="ModifierOrder"/>
        <module name="SimplifyBooleanReturn"/>
        <module name="SimplifyBooleanExpression"/>
        <module name="StringLiteralEquality"/>
        <module name="DefaultComesLast"/>
        <module name="RedundantModifier"/>

        <!-- Imports -->
        <module name="RedundantImport"/>
        <module name="UnusedImports"/>
        <module name="IllegalImport">
            <property name="illegalPkgs" value="net.minecraft.server, org.bukkit.craftbukkit"/>
        </module>

        <module name="IllegalTokenText">
            <!-- Avoid unicode literals for characters with escapes -->
            <property name="tokens" value="STRING_LITERAL, CHAR_LITERAL"/>
            <property name="format"
                      value="\\u00(08|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="Avoid using corresponding octal or Unicode escape."/>
        </module>

        <!-- Blocks -->
        <module name="LeftCurly"/>
        <module name="RightCurly"/>
        <module name="RightCurly">
            <!-- For these tokens, the brace should be on its own line -->
            <property name="option" value="alone"/>
            <property name="tokens"
                      value="CLASS_DEF, METHOD_DEF, CTOR_DEF, LITERAL_FOR, LITERAL_WHILE, LITERAL_DO, STATIC_INIT, INSTANCE_INIT"/>
        </module>
        <module name="EmptyBlock">
            <property name="option" value="TEXT"/>
            <property name="tokens"
                      value="LITERAL_TRY, LITERAL_CATCH, LITERAL_FINALLY, LITERAL_IF, LITERAL_ELSE, LITERAL_SWITCH"/>
        </module>

        <!-- Whitespace -->
        <module name="ParenPad"/>
        <module name="TypecastParenPad"/>
        <module name="MethodParamPad"/>
        <module name="WhitespaceAfter"/>
        <module name="NoWhitespaceAfter"/>
        <module name="NoWhitespaceBefore">
            <property name="allowLineBreaks" value="true"/>
        </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="WhitespaceAround">
            <property name="allowEmptyConstructors" value="true"/>
            <property name="allowEmptyMethods" value="true"/>
            <!--<property name="allowEmptyTypes" value="true"/>-->
            <!--<property name="allowEmptyLoops" value="true"/>-->
            <message key="ws.notFollowed" value="WhitespaceAround: ''{0}'' is not followed by whitespace."/>
            <message key="ws.notPreceded" value="WhitespaceAround: ''{0}'' is not preceded with whitespace."/>
            <!-- RCURLY exempted due to incorrect checking on annotation array literals -->
            <!-- See @ToString in GlowOfflinePlayer and MetadataMap -->
            <property name="tokens"
                      value="ASSIGN, BAND, BAND_ASSIGN, BOR, BOR_ASSIGN, BSR,
                      BSR_ASSIGN, BXOR, BXOR_ASSIGN, COLON, DIV, DIV_ASSIGN,
                      DO_WHILE, EQUAL, GE, GT, LAND, LCURLY, LE, LITERAL_ASSERT,
                      LITERAL_CATCH, LITERAL_DO, LITERAL_ELSE, LITERAL_FINALLY,
                      LITERAL_FOR, LITERAL_IF, LITERAL_RETURN, LITERAL_SWITCH,
                      LITERAL_SYNCHRONIZED, LITERAL_TRY, LITERAL_WHILE, LOR, LT,
                      MINUS, MINUS_ASSIGN, MOD, MOD_ASSIGN, NOT_EQUAL, PLUS,
                      PLUS_ASSIGN, QUESTION, SL, SLIST, SL_ASSIGN, SR,
                      SR_ASSIGN, STAR, STAR_ASSIGN, TYPE_EXTENSION_AND"/>
        </module>

        <!-- Naming conventions -->
        <module name="ClassTypeParameterName">
            <message key="name.invalidPattern" value="Class type name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="LocalFinalVariableName">
            <message key="name.invalidPattern" value="Local final variable name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="LocalVariableName">
            <message key="name.invalidPattern" value="Local variable name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="MemberName">
            <message key="name.invalidPattern" value="Member name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="MethodName">
            <!-- Allow _INVALID_ method names -->
            <property name="format" value="^(?:_INVALID_)?[a-z][a-zA-Z0-9_]*$"/>
            <message key="name.invalidPattern" value="Method name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="MethodTypeParameterName">
            <message key="name.invalidPattern" value="Method type parameter name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="PackageName">
            <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]*)*$"/>
            <message key="name.invalidPattern" value="Package name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="ParameterName">
            <message key="name.invalidPattern" value="Parameter name ''{0}'' must match pattern ''{1}''."/>
        </module>
        <module name="TypeName">
            <message key="name.invalidPattern" value="Type name ''{0}'' must match pattern ''{1}''."/>
        </module>

        <!-- Checks that the code doesn't yet pass -->
        <!--<module name="AvoidStarImport"/>-->
        <!--<module name="NeedBraces"/>-->
        <!--<module name="MissingSwitchDefault"/>-->
        <!--<module name="OneStatementPerLine"/>-->
        <!--<module name="Indentation"/>-->

        <!-- Checks in future checkstyle versions -->
        <!--<module name="OneTopLevelClass"/>-->
        <!--<module name="NoLineWrap"/>-->
        <!--<module name="EmptyLineSeparator">
            <property name="allowNoEmptyLineBetweenFields" value="true"/>
        </module>-->
        <!--<module name="OverloadMethodsDeclarationOrder"/>-->
        <!--<module name="VariableDeclarationUsageDistance"/>-->
        <!--<module name="AbbreviationAsWordInName">
           <property name="ignoreFinal" value="false"/>
           <property name="allowedAbbreviationLength" value="1"/>
        </module>-->
        <!--<module name="CustomImportOrder">
            <property name="thirdPartyPackageRegExp" value=".*"/>
            <property name="sortImportsInGroupAlphabetically" value="true"/>
            <property name="customImportOrderRules" value="STATIC###SPECIAL_IMPORTS###THIRD_PARTY_PACKAGE###STANDARD_JAVA_PACKAGE"/>
        </module>-->
    </module>
</module>