checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
          "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
          "https://checkstyle.org/dtds/configuration_1_3.dtd">

<module name="Checker">
    <property name="severity" value="warning"/>
    <property name="fileExtensions" value="java"/>

    <!-- Checks for Size Violations -->
    <module name="FileLength">
        <property name="max" value="500"/>
    </module>
    <module name="LineLength">
        <property name="max" value="120"/>
    </module>

    <module name="TreeWalker">
        <!-- Checks for Naming Conventions -->
        <module name="MethodName"/>
        <module name="PackageName"/>
        <module name="TypeName"/>
        <module name="ParameterName"/>
        <module name="LocalVariableName"/>
        <module name="MemberName"/>

        <!-- Checks for imports -->
        <module name="AvoidStarImport"/>
        <module name="IllegalImport"/>
        <module name="RedundantImport"/>
        <module name="UnusedImports"/>

        <!-- Checks for Size Violations -->
        <module name="MethodLength">
            <property name="max" value="50"/>
        </module>

        <!-- Checks for whitespace -->
        <module name="EmptyLineSeparator"/>
        <module name="GenericWhitespace"/>
        <module name="MethodParamPad"/>
        <module name="NoWhitespaceAfter"/>
        <module name="NoWhitespaceBefore"/>
        <module name="ParenPad"/>
        <module name="TypecastParenPad"/>
        <module name="WhitespaceAfter"/>
        <module name="WhitespaceAround"/>

        <!-- Modifier Checks -->
        <module name="ModifierOrder"/>
        <module name="RedundantModifier"/>

        <!-- Checks for blocks -->
        <module name="EmptyBlock"/>
        <module name="LeftCurly"/>
        <module name="RightCurly"/>
        <module name="NeedBraces"/>

        <!-- Checks for common coding problems -->
        <module name="EmptyStatement"/>
        <module name="EqualsHashCode"/>
        <module name="IllegalInstantiation"/>
        <module name="MissingSwitchDefault"/>
        <module name="SimplifyBooleanExpression"/>
        <module name="SimplifyBooleanReturn"/>
    </module>
</module>