checkstyle.xml

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

    <module name="SuppressionFilter">
        <property name="file" value="${checkStyleConfigDir}/checkstyle_suppressions.xml" />
    </module>

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

    <!-- Ensure trailling newline for compatibility -->
    <module name="NewlineAtEndOfFile">
        <property name="lineSeparator" value="lf"/>
    </module>

    <!-- Space after 'for' and 'if' -->
    <module name="RegexpSingleline">
        <property name="format" value="^\s*(for|if)\b[^ ]"/>
        <property name="message" value="Space needed before opening parenthesis."/>
    </module>

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

    <module name="TreeWalker">
        <!-- Checks for uncommented main() methods (debugging leftovers). -->
        <!-- Checks that long constants are defined with an upper ell. -->
        <!-- See http://checkstyle.sourceforge.net/config_misc.html#UpperEll -->
        <module name="UpperEll" />

        <!-- Checks the style of array type definitions. -->
        <!-- See http://checkstyle.sourceforge.net/config_misc.html#ArrayTypeStyle -->
        <module name="ArrayTypeStyle" />

        <!-- Checks that the outer type name and the file name match. -->
        <!-- See http://checkstyle.sourceforge.net/config_misc.html#OuterTypeFilename -->
        <module name="OuterTypeFilename" />

        <!-- Validates Javadoc comments to help ensure they are well formed. -->
        <!-- See http://checkstyle.sourceforge.net/config_javadoc.html#JavadocStyle -->
        <module name="JavadocStyle" />
        <module name="JavadocType">
            <property name="scope" value="public"/>
        </module>

        <!-- Each of these naming modules validates identifiers for particular
                code elements. -->
        <!-- See http://checkstyle.sourceforge.net/config_naming.html -->
        <module name="ConstantName">
            <property name="format" value="^[A-Z][A-Z0-9\$]*(_[A-Z0-9\$]+)*$" />
        </module>
        <module name="LocalFinalVariableName" />
        <module name="LocalVariableName" />
        <module name="MemberName">
            <property name="format" value="^[a-z][a-zA-Z0-9_\$]*$" />
        </module>
        <module name="MethodName" >
            <property name="format" value="^[a-z][a-zA-Z0-9]*(_[a-zA-Z0-9]+)*$"/>
        </module>
        <module name="PackageName" />
        <module name="ParameterName" />
        <module name="StaticVariableName" />
        <module name="TypeName" />

        <!-- Allow common trailing comments used to describe suppressions -->
        <module name="TrailingComment">
          <property name="legalComment" value="^Public API.?$|^NOPMD.*$" />
        </module>

        <!-- Checks for imports. -->
        <!-- See http://checkstyle.sourceforge.net/config_imports.html -->
        <module name="AvoidStarImport"/>
        <module name="RedundantImport"/>
        <module name="UnusedImports"/>
        <!-- Default sun.* packages -->
        <module name="IllegalImport">
            <property name="illegalPkgs" value="sun" />
            <message key="import.illegal" value="Import from illegal package - {0}. Programs that contain direct calls to the sun.* packages are not 100% Pure Java." />
        </module>
        <!-- Prevent importing JUnit 3 classes and Assert methods -->
        <module name="IllegalImport">
            <property name="illegalPkgs" value="junit" />
            <message key="import.illegal" value="Import from illegal package - {0}. Tests are written in JUnit 4, use org.junit.* equivalents." />
        </module>
        <!-- Prevent importing Mockito matchers directly -->
        <module name="IllegalImport">
            <property name="illegalPkgs" value="org.mockito.internal" />
            <message key="import.illegal" value="Import from illegal package - {0}. Use org.mockito.Matchers to instantiate argument matchers." />
        </module>

        <!-- ArgumentMatchers isn't available internally, the same methods are available on org.mockito.Mockito. -->
        <module name="IllegalImport">
            <property name="illegalClasses" value="org\.mockito\.ArgumentMatchers.*" />
            <property name="regexp" value="true" />
            <message key="import.illegal" value="Import from illegal class - {0}. Use org.mockito.Mockito to statically import matcher methods." />
        </module>

        <module name="ImportOrder">
          <!-- Checks for out of order import statements. -->

          <property name="sortStaticImportsAlphabetically" value="true"/>
           <property name="severity" value="error"/>
           <property name="groups" value="*"/>
           <!-- This ensures that static imports go first. -->
           <property name="option" value="top"/>
           <property name="tokens" value="STATIC_IMPORT, IMPORT"/>
           <property name="separated" value="true" />
         </module>

        <!-- Checks for whitespace. -->
        <!-- See http://checkstyle.sourceforge.net/config_whitespace.html -->
        <module name="GenericWhitespace" />
        <module name="MethodParamPad" />
        <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" />


        <!-- Modifier Checks. -->
        <!-- See http://checkstyle.sourceforge.net/config_modifier.html -->
        <module name="ModifierOrder" />

        <!-- Checks for blocks. -->
        <!-- See http://checkstyle.sourceforge.net/config_blocks.html -->
        <module name="AvoidNestedBlocks">
          <property name="allowInSwitchCase" value="true" />
        </module>
        <module name="EmptyBlock" >
            <property name="option" value="text"/>
        </module>
        <module name="NeedBraces"/>

        <module name="LeftCurly" />
        <module name="RightCurly">
            <property name="tokens"
                      value="LITERAL_TRY, LITERAL_CATCH, LITERAL_FINALLY, LITERAL_ELSE" />
        </module>

        <!-- Checks for common coding problems. -->
        <!-- See http://checkstyle.sourceforge.net/config_coding.html -->
        <module name="CovariantEquals" />
        <module name="DefaultComesLast" />
        <module name="EmptyStatement" />
        <module name="EqualsHashCode" />
        <module name="NoClone" />
        <module name="NoFinalizer" />
        <module name="OneStatementPerLine" />
        <module name="IllegalInstantiation"/>
        <module name="SimplifyBooleanExpression" />
        <module name="SimplifyBooleanReturn" />
        <module name="StringLiteralEquality" />
        <module name="UnnecessaryParentheses" />
        <module name="LineLength">
            <property name="max" value="100" />
        </module>

        <!-- Checks for class design. -->
        <!-- See http://checkstyle.sourceforge.net/config_design.html -->
        <module name="FinalClass" />
        <module name="InterfaceIsType" />
    </module>
</module>