checkstyle.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE module PUBLIC
        "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
        "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">

<module name="Checker">

    <module name="TreeWalker">

        <!-- Checks for redundant import statements. -->
        <module name="RedundantImport">
            <property name="severity" value="error"/>
        </module>

        <!-- Checks for unused import statements. -->
        <module name="UnusedImports">
            <property name="processJavadoc" value="true"/>
        </module>

        <!-- Checks that the whitespace around the Generic tokens are correct. -->
        <module name="GenericWhitespace"/>

        <!-- Checks for empty line separators. -->
        <module name="EmptyLineSeparator">
            <property name="tokens" value="CLASS_DEF, ENUM_DEF, METHOD_DEF"/>

            <property name="allowNoEmptyLineBetweenFields" value="true"/>
        </module>

        <!-- Detects empty statements (standalone ";" semicolon). -->
        <module name="EmptyStatement"/>

        <!-- Checks the policy on the padding of parentheses for typecasts. -->
        <module name="TypecastParenPad"/>

        <!-- Checks that chosen statements are not line-wrapped. -->
        <module name="NoLineWrap"/>

        <!-- Checks for imports from a set of illegal packages -->
        <module name="IllegalImport">
            <property name="illegalPkgs"
                      value="sun.*, com.google.appengine.labs.repackaged, com.google.appengine.repackaged, com.google.api.client.repackaged"/>
        </module>

        <!-- Validates identifiers for packages. -->
        <module name="PackageName">
            <property name="format"
                      value="^[a-z]+(\.[a-z][a-z0-9]*)*$"/>
        </module>

        <!-- Checks the padding between an identifier and the left parenthesis of a parameter list. -->
        <module name="MethodParamPad"/>

        <!-- Checks that a token is surrounded by whitespace. -->
        <module name="WhitespaceAround">
            <property name="allowEmptyConstructors" value="true"/>
            <property name="allowEmptyMethods" value="true"/>
            <property name="allowEmptyTypes" value="true"/>
            <property name="allowEmptyLoops" value="true"/>
        </module>

        <!-- Checks for braces around control structures. -->
        <module name="NeedBraces">
            <property name="tokens" value="LITERAL_IF, LITERAL_ELSE, LITERAL_FOR, LITERAL_WHILE, LITERAL_DO"/>
        </module>
    </module>

</module>