etc/config/checkstyle-verify.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--

    Copyright (c) 2015, 2020 Oracle and/or its affiliates. All rights reserved.

    This program and the accompanying materials are made available under the
    terms of the Eclipse Public License v. 2.0, which is available at
    http://www.eclipse.org/legal/epl-2.0.

    This Source Code may also be made available under the following Secondary
    Licenses when the conditions for such availability set forth in the
    Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
    version 2 with the GNU Classpath Exception, which is available at
    https://www.gnu.org/software/classpath/license.html.

    SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0

-->

<!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"/>

    <!-- Checks for whitespace                               -->
    <!-- See http://checkstyle.sf.net/config_whitespace.html -->
    <module name="FileTabCharacter">
        <property name="eachLine" value="true"/>
    </module>

    <module name="LineLength">
        <property name="max" value="130"/>
        <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://|@see| \* |@link|TODO|@todo|@version"/>
        <property name="fileExtensions" value="java"/>
    </module>

    <module name="TreeWalker">
        <property name="tabWidth" value="4"/>

        <module name="OuterTypeFilename"/>

        <module name="AvoidStarImport"/>
        <!--<module name="UnusedImports"/>-->

        <module name="OneTopLevelClass"/>
        <module name="NoLineWrap"/>
        <module name="MethodParamPad"/>
        <module name="NoWhitespaceAfter"/>
        <module name="NoWhitespaceBefore"/>
        <module name="OperatorWrap"/>
        <module name="ParenPad"/>
        <module name="TypecastParenPad"/>
        <module name="WhitespaceAfter"/>

        <module name="EmptyBlock">
            <property name="option" value="TEXT"/>
            <property name="tokens" value="LITERAL_TRY, LITERAL_FINALLY, LITERAL_IF, LITERAL_ELSE, LITERAL_SWITCH"/>
        </module>

        <module name="NeedBraces">
            <property name="allowSingleLineStatement" value="true"/>
        </module>
        <module name="LeftCurly">
            <!-- without literal LAMBDA -->
            <property name="tokens" value="ANNOTATION_DEF, CLASS_DEF, CTOR_DEF, ENUM_CONSTANT_DEF, ENUM_DEF,
                                           INTERFACE_DEF, LITERAL_CASE, LITERAL_CATCH, LITERAL_DEFAULT,
                                           LITERAL_DO, LITERAL_ELSE, LITERAL_FINALLY, LITERAL_FOR, LITERAL_IF,
                                           LITERAL_SWITCH, LITERAL_SYNCHRONIZED, LITERAL_TRY, LITERAL_WHILE,
                                           METHOD_DEF, OBJBLOCK, STATIC_INIT" />
        </module>
        <module name="RightCurly">
            <property name="option" value="alone"/>
            <!-- without literal LITERAL_TRY, LITERAL_CATCH, LITERAL_IF -->
            <property name="tokens"
                    value="LITERAL_FOR, LITERAL_WHILE, LITERAL_FINALLY, LITERAL_ELSE"/>
        </module>

        <module name="WhitespaceAround">
            <!-- Removed static initializer issues: RCURLY, SLIST -->
            <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_ASSERT, 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, SL_ASSIGN, SR, SR_ASSIGN, STAR, STAR_ASSIGN,
                            TYPE_EXTENSION_AND"/>
            <property name="allowEmptyConstructors" value="true"/>
            <property name="allowEmptyMethods" value="true"/>
            <property name="allowEmptyTypes" value="true"/>
            <property name="allowEmptyLoops" value="true"/>
            <message key="ws.notFollowed"
                    value="WhitespaceAround: ''{0}'' is not followed by whitespace. Empty blocks may only be represented as '{}' when not part of a multi-block statement (4.1.3)"/>
            <message key="ws.notPreceded"
                    value="WhitespaceAround: ''{0}'' is not preceded with whitespace."/>
        </module>

        <module name="OneStatementPerLine"/>
        <module name="FallThrough"/>
        <module name="UpperEll"/>
        <module name="ModifierOrder"/>

        <module name="SeparatorWrap">
            <property name="tokens" value="DOT"/>
            <property name="option" value="nl"/>
        </module>
        <module name="SeparatorWrap">
            <property name="tokens" value="COMMA"/>
            <property name="option" value="EOL"/>
        </module>

        <module name="NoFinalizer"/>

        <module name="GenericWhitespace">
            <message key="ws.followed"
                    value="GenericWhitespace ''{0}'' is followed by whitespace."/>
            <message key="ws.preceded"
                    value="GenericWhitespace ''{0}'' is preceded with whitespace."/>
            <message key="ws.illegalFollow"
                    value="GenericWhitespace ''{0}'' should followed by whitespace."/>
            <message key="ws.notPreceded"
                    value="GenericWhitespace ''{0}'' is not preceded with whitespace."/>
        </module>

        <module name="AnnotationLocation">
            <property name="tokens" value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF"/>
        </module>
        <module name="AnnotationLocation">
            <property name="tokens" value="VARIABLE_DEF"/>
            <property name="allowSamelineMultipleAnnotations" value="true"/>
        </module>

        <!-- No Trailing Whitespaces. -->
        <module name="RegexpSinglelineJava">
            <property name="format" value="[ ]+$"/>
            <property name="message" value="File contains trailing whitespace."/>
        </module>
    </module>
</module>