OuterTypeNumberCheck.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"/>

    <!-- do not change severity to 'error', as that will hide errors caused by exceptions -->
    <property name="severity" value="warning"/>

    <!-- haltOnException is required for exception fixes and reporting of all exceptions -->
    <property name="haltOnException" value="false"/>

    <!-- BeforeExecutionFileFilters is required for sources of java9 -->
    <module name="BeforeExecutionExclusionFileFilter">
        <property name="fileNamePattern" value="module\-info\.java$" />
    </module>

    <module name="TreeWalker">
         <module name="OuterTypeNumber">
             <property name="max" value="2"/>
         </module>
         <!-- Example of sevntu.checkstyle Check usage -->
         <!-- <module name="NestedSwitchCheck"/> -->

         <!-- usuppress javadoc parsing errors, as we test Check not a parser -->
         <module name="SuppressionXpathSingleFilter">
            <property name="message" value="Javadoc comment at column \d+ has parse error"/>
         </module>
    </module>
    <!-- Example of filter -->
    <!--
    <module name="SeverityMatchFilter">
        <property name="severity" value="warning"/>
        <property name="acceptOnMatch" value="false"/>
    </module>
    -->

    <!-- as we run on regression even on non-compiled files we need to skip exceptions on them -->
    <module name="SuppressionSingleFilter">
      <property name="message" value="Exception occurred while parsing"/>
      <property name="checks" value="Checker"/>
    </module>
</module>