checkstyle.xml

<!DOCTYPE module PUBLIC
        "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
        "https://checkstyle.org/dtds/configuration_1_3.dtd">

<module name="Checker">

        <module name="SuppressionFilter">
          <property name="file" value="suppressions.xml"/>
          <property name="optional" value="false"/>
        </module>

        <!-- Formatting Check: Enforces a maximum line length of 100 characters -->
        <module name="LineLength">
            <property name="max" value="120"/>
        </module>

        <!-- Code Structure Check: Limits the length of a file to 1000 lines -->
        <module name="FileLength">
            <property name="max" value="1000"/>
        </module>

        <!-- Code Structure Check: Enforces Javadoc comments for package-info.java files -->
        <module name="JavadocPackage"/>

    <!-- TreeWalker Module: Performs checks on the abstract syntax tree -->
    <module name="TreeWalker">

        <!-- Formatting Check: Enforces whitespace around certain tokens -->
        <module name="WhitespaceAround">
            <property name="allowEmptyConstructors" value="true"/>
            <property name="allowEmptyMethods" value="true"/>
        </module>

        <!-- Code Structure Check: Disallows empty blocks -->
        <module name="EmptyBlock">
            <property name="option" value="text"/>
        </module>

        <!-- Code Structure Check: Enforces the use of braces for control statements -->
        <module name="NeedBraces"/>

        <!-- Formatting Check: Enforces consistent whitespace usage -->
        <module name="GenericWhitespace"/>


        <!-- Code Structure Check: Checks for redundant import statements -->
        <module name="RedundantImport"/>

        <!-- Code Structure Check: Disallows star import statements -->
        <module name="AvoidStarImport"/>

        <!-- Code Structure Check: Checks the placement of left curly braces -->
        <module name="LeftCurly"></module>

        <!-- Naming Convention Check: Enforces naming conventions for local final variables -->
        <module name="LocalFinalVariableName"/>

        <!-- Naming Convention Check: Enforces naming conventions for local variables -->
        <module name="LocalVariableName"/>

        <!-- Naming Convention Check: Enforces naming conventions for member variables -->
        <module name="MemberName"/>

        <!-- Naming Convention Check: Enforces naming conventions for method names -->
        <module name="MethodName"/>

        <!-- Naming Convention Check: Enforces naming conventions for package names -->
        <module name="PackageName"/>

        <!-- Naming Convention Check: Enforces naming conventions for method parameters -->
        <module name="ParameterName"/>

        <!-- Naming Convention Check: Enforces naming conventions for static variables -->
        <module name="StaticVariableName"/>

        <!-- Naming Convention Check: Enforces naming conventions for type names (classes, interfaces, enums, etc.) -->
        <module name="TypeName"/>

        <!-- Code Structure Check: Disallows unused import statements -->
        <module name="UnusedImports"/>

        <!-- Code Structure Check: Disallows unused private fields -->
        <!-- <module name="UnusedPrivateField"/> -->

        <!-- Code Structure Check: Enforces Javadoc comments for methods and classes -->
        <module name="JavadocMethod"/>
        <module name="JavadocType"/>

        <!-- Code Structure Check: Disallows trailing whitespace -->
        <module name="NoWhitespaceAfter"/>

        <!-- Code Structure Check: Disallows whitespace before a semicolon -->
        <module name="NoWhitespaceBefore"/>

        <!-- Add: // CHECKSTYLE:OFF to the top of the file for which you want to skip checkstyle checks. -->
        <module name="SuppressionCommentFilter"/>
    </module>

</module>