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"/>

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

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

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

  <module name="LineLength">
    <property name="severity" value="warning"/>
    <property name="max" value="100"/>
    <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
  </module>

  <module name="TreeWalker">
    <module name="Indentation"> <!-- TODO: indent by 2 -->
      <property name="basicOffset" value="4"/>
      <property name="braceAdjustment" value="0"/>
      <property name="caseIndent" value="4"/>
      <property name="throwsIndent" value="4"/>
      <property name="lineWrappingIndentation" value="4"/>
      <property name="arrayInitIndent" value="4"/>
    </module>
    <module name="CommentsIndentation"/>

    <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>

    <!-- Code -->
    <module name="OuterTypeFilename"/>
    <module name="OneTopLevelClass"/>
    <module name="NoLineWrap"/>
    <module name="OneStatementPerLine"/>
    <module name="ArrayTypeStyle"/>
    <module name="MultipleVariableDeclarations"/>
    <module name="MissingSwitchDefault"/>
    <module name="FallThrough"/>
    <module name="UpperEll"/>
    <module name="ModifierOrder"/>
    <module name="EmptyLineSeparator">
      <property name="allowNoEmptyLineBetweenFields" value="true"/>
    </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="SeparatorWrapMethodRef"/>
      <property name="tokens" value="METHOD_REF"/>
      <property name="option" value="nl"/>
    </module>
    <module name="NoFinalizer"/>
    <module name="OverloadMethodsDeclarationOrder"/>
    <module name="VariableDeclarationUsageDistance">
      <property name="severity" value="warning"/>
    </module>
    <module name="OperatorWrap">
      <property name="option" value="NL"/>
      <property name="tokens"
        value="BAND, BOR, BSR, BXOR, DIV, EQUAL, GE, GT, LAND, LE, LITERAL_INSTANCEOF, LOR, LT, MINUS, MOD, NOT_EQUAL, PLUS, QUESTION, SL, SR, STAR, METHOD_REF "/>
    </module>
    <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="true"/>
    </module>

    <!-- Javadocs -->
    <module name="NonEmptyAtclauseDescription"/>
    <module name="JavadocTagContinuationIndentation"/>
    <module name="SummaryJavadoc">
      <property name="severity" value="warning"/>
      <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="severity" value="warning"/>
      <property name="scope" value="public"/>
      <property name="allowMissingParamTags" value="true"/>
      <property name="validateThrows" value="false"/>
      <property name="allowMissingReturnTag" value="true"/>
      <property name="allowedAnnotations" value="Override, Test"/>
    </module>
    <module name="MissingJavadocMethod">
      <property name="severity" value="warning"/>
      <property name="minLineCount" value="2"/>
      <property name="scope" value="public"/>
    </module>
    <module name="SingleLineJavadoc">
      <property name="severity" value="warning"/>
      <property name="ignoreInlineTags" value="false"/>
    </module>

    <!-- Imports -->
    <module name="AvoidStarImport"/>
    <module name="CustomImportOrder">
      <property name="sortImportsInGroupAlphabetically" value="true"/>
      <property name="separateLineBetweenGroups" value="true"/>
      <property name="customImportOrderRules" value="STATIC###THIRD_PARTY_PACKAGE"/>
      <property name="tokens" value="IMPORT, STATIC_IMPORT, PACKAGE_DEF"/>
    </module>
    <module name="RedundantImport"/>
    <module name="UnusedImports"/>
    <module name="IllegalImport">
      <property name="illegalPkgs" value="net.minecraft.server, org.bukkit.craftbukkit"/>
    </module>

    <!-- Blocks -->
    <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="NeedBraces"/>
    <module name="LeftCurly"/>
    <module name="RightCurly">
      <property name="id" value="RightCurlySame"/>
      <property name="option" value="same"/>
      <property name="tokens"
       value="LITERAL_TRY, LITERAL_CATCH, LITERAL_FINALLY, LITERAL_IF, LITERAL_ELSE,
              LITERAL_DO, CLASS_DEF, METHOD_DEF, CTOR_DEF, LITERAL_FOR, LITERAL_WHILE, STATIC_INIT,
              INSTANCE_INIT, ANNOTATION_DEF, ENUM_DEF"/>
    </module>
    <module name="EmptyCatchBlock">
      <property name="exceptionVariableName" value="expected"/>
    </module>

    <!-- Whitespace -->
    <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. 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="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="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"/>

    <!-- Naming conventions -->
    <module name="PackageName">
      <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]*)*$"/>
      <message key="name.invalidPattern" value="Package name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="TypeName">
      <message key="name.invalidPattern" value="Type name ''{0}'' must match pattern ''{1}''."/>
    </module>
    <module name="AbbreviationAsWordInName">
      <property name="severity" value="warning"/>
      <property name="ignoreFinal" value="false"/>
      <property name="allowedAbbreviationLength" value="1"/>
    </module>
    <module name="MethodName">
      <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9_]*$"/>
      <message key="name.invalidPattern"
        value="Method name ''{0}'' must match pattern ''{1}''."/>
    </module>
  </module>
</module>