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">
<!--
  Checkstyle configuration that checks the sun coding conventions from:

    - the Java Language Specification at
      http://java.sun.com/docs/books/jls/second_edition/html/index.html

    - the Sun Code Conventions at http://java.sun.com/docs/codeconv/

    - the Javadoc guidelines at
      http://java.sun.com/j2se/javadoc/writingdoccomments/index.html

    - the JDK Api documentation http://java.sun.com/j2se/docs/api/index.html

    - some best practices

  Checkstyle is very configurable. Be sure to read the documentation at
  http://checkstyle.sf.net (or in your downloaded distribution).

  Most Checks are configurable, be sure to consult the documentation.

  To completely disable a check, just comment it out or delete it from the file.

  Finally, it is worth reading the documentation.
-->

<module name="Checker">
    <module name="SuppressionFilter">
        <property name="file" value="checkstyle-suppressions.xml"/>
    </module>

    <property name="charset" value="UTF-8"/>
    <!-- Checks for Size Violations.                    -->
    <!-- See http://checkstyle.sf.net/config_sizes.html -->
    <module name="FileLength">
        <property name="max" value="5000"/>
    </module>
    <!-- Checks for whitespace                               -->
    <!-- See http://checkstyle.sf.net/config_whitespace.html -->
    <module name="FileTabCharacter"/>
    <!-- Checks for existence of a 'package-info.java' in every package -->
    <!-- See https://checkstyle.sourceforge.io/config_javadoc.html#JavadocPackage -->
    <module name="JavadocPackage"/>
    <module name="TreeWalker">
        <module name="SuppressionCommentFilter"/>
        <module name="DeclarationOrder">
            <property name="id" value="NoTests"/>
        </module>
        <module name="PackageName"/>
        <module name="TypeName"/>
        <module name="IllegalImport"/> <!-- defaults to sun.* packages -->
        <module name="IllegalImport">
            <!--
              Log4J and SLF4J are banned because anything logged with them doesn't show
              up in the web console. Use java.util.logging instead.
             -->
            <property name="illegalPkgs" value="clover,
                                                com.google.common.collect,
                                                junit.framework,
                                                org.apache.commons.lang,
                                                org.apache.log4j,
                                                org.slf4j"/>
            <property name="illegalClasses" value="javax.annotation.Nonnull"/>
        </module>
        <module name="RedundantImport"/>
        <module name="UnusedImports"/>
        <!-- Checks for whitespace                               -->
        <!-- See http://checkstyle.sf.net/config_whitespace.html -->
        <module name="EmptyForIteratorPad"/>
        <module name="EmptyLineSeparator">
            <!-- All the normal except VARIABLE_DEF -->
            <property name="tokens" value="CLASS_DEF, CTOR_DEF, ENUM_DEF, IMPORT, INSTANCE_INIT, INTERFACE_DEF, METHOD_DEF, PACKAGE_DEF, STATIC_INIT"/>
            <property name="allowMultipleEmptyLines" value="false"/>
            <property name="allowMultipleEmptyLinesInsideClassMembers" value="false"/>
        </module>
        <module name="EmptyLineAfterDefinition">
            <!-- Disabled for enums so "compact" defintions - with only enum values - don't require an initial blank line -->
            <property name="tokens" value="CLASS_DEF, INTERFACE_DEF"/>
        </module>
        <module name="GenericWhitespace"/>
        <module name="MethodParamPad"/>
        <module name="NoWhitespaceAfter"/>
        <module name="NoWhitespaceBefore"/>
        <module name="OperatorWrap">
            <!-- The below settings contain everything except: COLON,PLUS,QUESTION -->
            <!-- PLUS only because there are already too many usages -->
            <property name="tokens"
                      value="ASSIGN,BAND,BAND_ASSIGN,BOR,BOR_ASSIGN,BSR,BSR_ASSIGN,BXOR,BXOR_ASSIGN,DIV,DIV_ASSIGN,
                      EQUAL,GE,GT,LAND,LE,LITERAL_INSTANCEOF,LOR,LT,MINUS,MINUS_ASSIGN,MOD,MOD_ASSIGN,NOT_EQUAL,
                      PLUS_ASSIGN,SL,SL_ASSIGN,SR,SR_ASSIGN,STAR,STAR_ASSIGN,METHOD_REF"/>
            <property name="option" value="EOL"/>
        </module>
        <module name="ParenPad"/>
        <module name="SingleSpaceSeparator"/>
        <module name="TypecastParenPad"/>
        <module name="WhitespaceAfter"/>
        <module name="BitbucketWhitespaceAround">
            <property name="tokens"
                      value="ASSIGN, BAND, BAND_ASSIGN, BOR, BOR_ASSIGN, BSR, BSR_ASSIGN, BXOR, BXOR_ASSIGN, COLON, DIV, DIV_ASSIGN, EQUAL, GE, GT, LAMBDA, LAND, LE, LITERAL_ASSERT, LITERAL_CATCH, LITERAL_DO, LITERAL_ELSE, LITERAL_FINALLY, LITERAL_FOR, LITERAL_IF, LITERAL_RETURN, 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"/>
            <property name="ignoredParents" value="ANNOTATION_MEMBER_VALUE_PAIR"/>
        </module>
        <!-- Modifier Checks                                    -->
        <!-- See http://checkstyle.sf.net/config_modifiers.html -->
        <module name="ModifierOrder"/>
        <module name="RedundantModifier">
            <property name="tokens" value="VARIABLE_DEF, ANNOTATION_FIELD_DEF"/>
        </module>
        <!-- Checks for blocks. You know, those {}'s         -->
        <!-- See http://checkstyle.sf.net/config_blocks.html -->
        <!-- TMP <module name="AvoidNestedBlocks"/>-->
        <module name="EmptyBlock">
            <property name="option" value="text"/>
        </module>
        <module name="LeftCurly"/>
        <module name="NeedBraces"/>
        <module name="RightCurly"/>
        <!-- Checks for common coding problems               -->
        <!-- See http://checkstyle.sf.net/config_coding.html -->
        <module name="EmptyStatement"/>
        <module name="EqualsHashCode"/>
        <module name="IllegalInstantiation"/>
        <module name="PackageDeclaration"/>
        <module name="SimplifyBooleanExpression"/>
        <!-- Miscellaneous other checks.                   -->
        <!-- See http://checkstyle.sf.net/config_misc.html -->
        <module name="ArrayTypeStyle"/>
        <!--<module name="FinalParameters"/>-->
        <!-- TMP <module name="TodoComment"/>-->
        <module name="UpperEll"/>
        <module name="AllowedAnnotations">
            <property name="annotation" value="EventListener"/>
            <property name="incompatibleAnnotations" value="Transactional,PreAuthorize"/>
        </module>

        <module name="GetClassTestContextUse"/>
        <module name="MissingDeprecated">
            <property name="skipNoJavadoc" value="true"/>
        </module>
    </module>
</module>