checkstyle.xml

<?xml version="1.0"?>
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  ~ Copyright 2015 Red Hat, Inc., and individual contributors
  ~ as indicated by the @author tags.
  ~
  ~ Licensed under the Apache License, Version 2.0 (the "License");
  ~ you may not use this file except in compliance with the License.
  ~ You may obtain a copy of the License at
  ~
  ~     http://www.apache.org/licenses/LICENSE-2.0
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  ~ distributed under the License is distributed on an "AS IS" BASIS,
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  ~ See the License for the specific language governing permissions and
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  -->

<!DOCTYPE module PUBLIC
        "-//Puppy Crawl//DTD Check Configuration 1.2//EN"
        "http://www.puppycrawl.com/dtds/configuration_1_2.dtd">

<module name="Checker">
    <module name="FileTabCharacter">
        <property name="eachLine" value="true"/>
    </module>

    <module name="RegexpSingleline">
        <!-- \s matches whitespace character, $ matches end of line -->
        <property name="format" value="\s+$"/>
        <property name="message" value="Line has trailing spaces."/>
    </module>

    <module name="TreeWalker">

        <property name="cacheFile" value="${checkstyle.cache.file}"/>

        <!-- Checks for imports  -->
        <module name="AvoidStarImport">
            <property name="allowStaticMemberImports" value="true"/>
        </module>
        <module name="RedundantImport"/>

        <module name="UnusedImports">
            <property name="processJavadoc" value="true"/>
        </module>

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

        <!-- Checks for blocks -->
        <module name="LeftCurly">
            <property name="option" value="eol"/>
            <property name="tokens" value="CLASS_DEF,CTOR_DEF,INTERFACE_DEF,METHOD_DEF,LITERAL_SWITCH,STATIC_INIT,INSTANCE_INIT"/>
        </module>

        <module name="EmptyStatement"/>
        <module name="EqualsHashCode"/>
        <module name="IllegalInstantiation"/>

        <!-- Miscellaneous other checks -->
        <module name="UpperEll"/>
        <module name="PackageAnnotation"/>
        <module name="CovariantEquals"/>
        <module name="ArrayTypeStyle"/>

    </module>

</module>