checkstyle.xml

<!DOCTYPE module PUBLIC
  "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
  "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">

  <!--
      Checkstyle configuration based on the Google coding conventions from:
      -  Google Java Style
         https://google.github.io/styleguide/javaguide.html
  -->

  <module name="Checker">

  <module name="NewlineAtEndOfFile"/>
  <module name="FileLength">
    <property name="max" value="10000"/>
  </module>
  <module name="FileTabCharacter"/>

  <!-- Trailing spaces -->
  <module name="RegexpSingleline">
    <property name="format" value="\s+$"/>
    <property name="message" value="Line has trailing spaces."/>
  </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 Javadoc comments.                     -->
    <!-- See http://checkstyle.sf.net/config_javadoc.html -->
    <module name="JavadocStyle"/>


    <!-- Checks for Naming Conventions.                  -->
    <!-- See http://checkstyle.sf.net/config_naming.html -->
    <!--<module name="ConstantName"/>-->
    <module name="LocalFinalVariableName"/>
    <module name="LocalVariableName"/>
    <module name="MemberName"/>
    <module name="MethodName"/>
    <module name="ParameterName"/>
    <module name="StaticVariableName"/>
    <module name="TypeName"/>
    <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>

    <!-- Checks for imports                              -->
    <!-- See http://checkstyle.sf.net/config_import.html -->
    <module name="AvoidStarImport"/>
    <module name="IllegalImport"/>
    <!-- defaults to sun.* packages -->
    <module name="RedundantImport"/>
    <module name="UnusedImports">
      <property name="processJavadoc" value="true"/>
    </module>


    <!-- Checks for Size Violations.                    -->
    <!-- See http://checkstyle.sf.net/config_sizes.html -->
    <module name="MethodLength">
      <property name="max" value="200"/>
    </module>


    <!-- Checks for whitespace                               -->
    <!-- See http://checkstyle.sf.net/config_whitespace.html -->
    <module name="GenericWhitespace"/>
    <module name="MethodParamPad"/>
    <module name="OperatorWrap"/>
    <module name="ParenPad"/>
    <module name="TypecastParenPad"/>
    <module name="WhitespaceAfter"/>
    <module name="WhitespaceAround">
      <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_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, LITERAL_ASSERT, TYPE_EXTENSION_AND"/>
    </module>


    <!-- Modifier Checks                                    -->
    <!-- See http://checkstyle.sf.net/config_modifiers.html -->
    <module name="ModifierOrder"/>
    <module name="RedundantModifier"/>


    <!-- Checks for blocks. You know, those { }'s         -->
    <!-- See http://checkstyle.sf.net/config_blocks.html -->
    <module name="AvoidNestedBlocks"/>
    <module name="LeftCurly"/>
    <module name="RightCurly"/>


    <!-- Checks for common coding problems               -->
    <!-- See http://checkstyle.sf.net/config_coding.html -->
    <module name="CovariantEquals"/>
    <module name="EmptyStatement"/>
    <module name="EqualsHashCode"/>
    <module name="IllegalInstantiation"/>
    <module name="SimplifyBooleanExpression"/>
    <module name="SimplifyBooleanReturn"/>

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

    <!-- Miscellaneous other checks.                   -->
    <!-- See http://checkstyle.sf.net/config_misc.html -->
    <module name="ArrayTypeStyle"/>
    <module name="UpperEll"/>

    <!-- Make the @SuppressWarnings annotations available to Checkstyle -->
    <module name="SuppressWarningsHolder" />
  </module>

  <!-- Filter out Checkstyle warnings that have been suppressed with the @SuppressWarnings annotation -->
  <module name="SuppressWarningsFilter" />
</module>