spring-boot/spring-boot-parent/src/checkstyle/checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC "-//Puppy Crawl//DTD Check Configuration 1.2//EN" "http://www.puppycrawl.com/dtds/configuration_1_2.dtd">
<module name="Checker">

	<!-- Root Checks -->
	<module name="RegexpHeader">
		<property name="headerFile" value="${checkstyle.header.file}" />
		<property name="fileExtensions" value="java" />
	</module>
	<module name="NewlineAtEndOfFile">
		<property name="lineSeparator" value="lf"/>
	</module>

	<!-- TreeWalker Checks -->
	<module name="TreeWalker">

		<!-- Annotations -->
		<module name="AnnotationUseStyle">
			<property name="elementStyle" value="compact" />
		</module>
		<module name="MissingOverride" />
		<module name="PackageAnnotation" />
		<module name="AnnotationLocation">
			<property name="allowSamelineSingleParameterlessAnnotation"
				value="false" />
		</module>

		<!-- Block Checks -->
		<module name="EmptyBlock">
			<property name="option" value="text" />
		</module>
		<module name="LeftCurly" />
		<module name="RightCurly">
			<property name="option" value="alone" />
		</module>
		<module name="NeedBraces" />
		<module name="AvoidNestedBlocks" />

		<!-- Class Design -->
		<module name="FinalClass" />
		<module name="InterfaceIsType" />
		<module name="HideUtilityClassConstructor" />
		<module name="MutableException" />
		<module name="InnerTypeLast" />
		<module name="OneTopLevelClass" />

		<!-- Coding -->
		<module name="CovariantEquals" />
		<module name="EmptyStatement" />
		<module name="EqualsHashCode" />
		<module name="InnerAssignment" />
		<module name="SimplifyBooleanExpression" />
		<module name="SimplifyBooleanReturn" />
		<module name="StringLiteralEquality" />
		<module name="NestedForDepth">
			<property name="max" value="3" />
		</module>
		<module name="NestedIfDepth">
			<property name="max" value="3" />
		</module>
		<module name="NestedTryDepth">
			<property name="max" value="3" />
		</module>
		<module name="MultipleVariableDeclarations" />
		<module name="RequireThis">
			<property name="checkMethods" value="false" />
		</module>
		<module name="OneStatementPerLine" />

		<!-- Imports -->
		<module name="AvoidStarImport" />
		<module name="AvoidStaticImport">
			<property name="excludes"
				value="org.junit.Assert.*, org.junit.Assume.*, org.junit.internal.matchers.ThrowableMessageMatcher.*, org.hamcrest.CoreMatchers.*, org.hamcrest.Matchers.*, org.springframework.boot.configurationprocessor.ConfigurationMetadataMatchers.*, org.springframework.boot.configurationprocessor.TestCompiler.*, org.mockito.Mockito.*, org.mockito.BDDMockito.*, org.mockito.Matchers.*, org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*, org.springframework.test.web.servlet.result.MockMvcResultMatchers.*, org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.*, org.springframework.security.test.web.servlet.setup.SecurityMockMvcConfigurers.*, org.springframework.hateoas.mvc.ControllerLinkBuilder.linkTo" />
		</module>
		<module name="IllegalImport" />
		<module name="RedundantImport" />
		<module name="UnusedImports">
			<property name="processJavadoc" value="true" />
		</module>
		<module name="ImportOrder">
			<property name="groups" value="java,/^javax?\./,*,org.springframework" />
			<property name="ordered" value="true" />
			<property name="separated" value="true" />
			<property name="option" value="bottom" />
			<property name="sortStaticImportsAlphabetically" value="true" />
		</module>

		<!-- Javadoc Comments -->
		<module name="JavadocType">
			<property name="scope" value="package"/>
			<property name="authorFormat" value=".+\s.+"/>
		</module>
		<module name="JavadocMethod">
			<property name="allowMissingJavadoc" value="true" />
		</module>
		<module name="JavadocVariable">
			<property name="scope" value="public"/>
		</module>
		<module name="JavadocStyle">
			<property name="checkEmptyJavadoc" value="true"/>
		</module>
		<module name="NonEmptyAtclauseDescription" />
		<module name="JavadocTagContinuationIndentation">
			<property name="offset" value="0"/>
		</module>
		<module name="AtclauseOrder">
			<property name="target" value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF"/>
    		<property name="tagOrder" value="@param, @author, @since, @see, @version, @serial, @deprecated"/>
		</module>
 		<module name="AtclauseOrder">
			<property name="target" value="METHOD_DEF, CTOR_DEF, VARIABLE_DEF"/>
    		<property name="tagOrder" value="@param, @return, @throws, @since, @deprecated, @see"/>
		</module>

		<!-- Miscellaneous -->
		<module name="CommentsIndentation" />
		<module name="UpperEll" />
		<module name="ArrayTypeStyle" />
		<module name="OuterTypeFilename" />

		<!-- Modifiers -->
		<module name="RedundantModifier" />

		<!-- Regexp -->
 		<module name="RegexpSinglelineJava">
			<property name="format" value="^\t* +\t*\S" />
			<property name="message"
				value="Line has leading space characters; indentation should be performed with tabs only." />
			<property name="ignoreComments" value="true" />
		</module>
 		<module name="RegexpSinglelineJava">
 			<property name="maximum" value="0"/>
			<property name="format" value="org\.mockito\.Mockito\.(when|doThrow|doAnswer)" />
			<property name="message"
				value="Please use BDDMockto imports." />
			<property name="ignoreComments" value="true" />
		</module>
		<module name="Regexp">
			<property name="format" value="[ \t]+$" />
			<property name="illegalPattern" value="true" />
			<property name="message" value="Trailing whitespace" />
		</module>

		<!-- Whitespace -->
		<module name="GenericWhitespace" />
		<module name="MethodParamPad" />
		<module name="NoWhitespaceAfter" >
			<property name="tokens" value="BNOT, DEC, DOT, INC, LNOT, UNARY_MINUS, UNARY_PLUS, ARRAY_DECLARATOR"/>
		</module>
		<module name="NoWhitespaceBefore" />
		<module name="ParenPad" />
		<module name="TypecastParenPad" />
		<module name="WhitespaceAfter" />
		<module name="WhitespaceAround" />

 	</module>
</module>