From 6aaf9f6280454b1653af65c456f3f7a1253fcac2 Mon Sep 17 00:00:00 2001
From: Jeff Ching <chingor@google.com>
Date: Thu, 8 Aug 2019 10:35:12 -0700
Subject: [PATCH 1/2] Update checkstyle rules and update
 maven-checkstyle-plugin to 3.1.0

---
 checkstyle.xml                                | 504 ++++++++----------
 pom.xml                                       |  54 +-
 samples/checkstyle.xml                        | 336 ------------
 .../dailymotion-simple-cmdline-sample/pom.xml |  54 +-
 4 files changed, 300 insertions(+), 648 deletions(-)
 delete mode 100644 samples/checkstyle.xml

diff --git a/checkstyle.xml b/checkstyle.xml
index 9d2f4bbe9..734575e4c 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -1,318 +1,266 @@
-<?xml version="1.0" encoding="UTF-8"?>
+<?xml version="1.0"?>
 <!DOCTYPE module PUBLIC
-    "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
-    "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
+    "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
+    "https://checkstyle.org/dtds/configuration_1_3.dtd">
 
-<!-- This is a checkstyle configuration file. For descriptions of
-what the following rules do, please see the checkstyle configuration
-page at http://checkstyle.sourceforge.net/config.html -->
+<!--
+    Checkstyle configuration that checks the Google coding conventions from Google Java Style
+    that can be found at https://google.github.io/styleguide/javaguide.html
 
-<module name="Checker">
+    Checkstyle is very configurable. Be sure to read the documentation at
+    http://checkstyle.sf.net (or in your downloaded distribution).
 
-  <module name="NewlineAtEndOfFile">
-    <property name="lineSeparator" value="lf"/>
-  </module>
+    To completely disable a check, just comment it out or delete it from the file.
 
-  <module name="RegexpSingleline">
-    <!-- Checks that FIXME is not used in comments.  TODO is preferred.
-    -->
-    <property name="format" value="((//.*)|(\*.*))FIXME" />
-    <property name="message" value='TODO is preferred to FIXME.  e.g. "TODO(johndoe): Refactor when v2 is released."' />
-  </module>
+    Authors: Max Vetrenko, Ruslan Diachenko, Roman Ivanov.
+ -->
 
-  <module name="RegexpSingleline">
-    <!-- Checks that TODOs are named.  (Actually, just that they are followed
-         by an open paren.)
-    -->
-    <property name="format" value="((//.*)|(\*.*))TODO[^(]" />
-    <property name="message" value='All TODOs should be named.  e.g. "TODO(johndoe): Refactor when v2 is released."' />
-  </module>
+<module name = "Checker">
+  <property name="charset" value="UTF-8"/>
+
+  <property name="severity" value="warning"/>
 
-  <module name="JavadocPackage">
-    <!-- Checks that each Java package has a Javadoc file used for commenting.
-      Only allows a package-info.java, not package.html. -->
+  <property name="fileExtensions" value="java, properties, xml"/>
+  <!-- Excludes all 'module-info.java' files              -->
+  <!-- See https://checkstyle.org/config_filefilters.html -->
+  <module name="BeforeExecutionExclusionFileFilter">
+    <property name="fileNamePattern" value="module\-info\.java$"/>
+  </module>
+  <!-- Checks for whitespace                               -->
+  <!-- See http://checkstyle.sf.net/config_whitespace.html -->
+  <module name="FileTabCharacter">
+    <property name="eachLine" value="true"/>
   </module>
 
-  <!-- All Java AST specific tests live under TreeWalker module. -->
   <module name="TreeWalker">
-
-    <!--
-
-    IMPORT CHECKS
-
-    -->
-
-    <module name="RedundantImport">
-      <!-- Checks for redundant import statements. -->
-      <property name="severity" value="error"/>
+    <module name="OuterTypeFilename"/>
+    <module name="IllegalTokenText">
+      <property name="tokens" value="STRING_LITERAL, CHAR_LITERAL"/>
+      <property name="format"
+          value="\\u00(09|0(a|A)|0(c|C)|0(d|D)|22|27|5(C|c))|\\(0(10|11|12|14|15|42|47)|134)"/>
+      <property name="message"
+          value="Consider using special escape sequence instead of octal value or Unicode escaped value."/>
     </module>
-
-    <module name="ImportOrder">
-      <!-- Checks for out of order import statements. -->
-
-      <property name="severity" value="warning"/>
-      <property name="groups" value="com.google,android,junit,net,org,java,javax"/>
-      <!-- This ensures that static imports go first. -->
-      <property name="option" value="top"/>
-      <property name="tokens" value="STATIC_IMPORT, IMPORT"/>
+    <module name="AvoidEscapedUnicodeCharacters">
+      <property name="allowEscapesForControlCharacters" value="true"/>
+      <property name="allowByTailComment" value="true"/>
+      <property name="allowNonPrintableEscapes" value="true"/>
     </module>
-
-    <!--
-
-    JAVADOC CHECKS
-
-    -->
-
-    <!-- Checks for Javadoc comments.                     -->
-    <!-- See http://checkstyle.sf.net/config_javadoc.html -->
-    <module name="JavadocMethod">
-      <property name="scope" value="protected"/>
-      <property name="severity" value="warning"/>
-      <property name="allowMissingJavadoc" value="true"/>
-      <property name="allowMissingParamTags" value="true"/>
-      <property name="allowMissingReturnTag" value="true"/>
-      <property name="allowMissingThrowsTags" value="true"/>
-      <property name="allowThrowsTagsForSubclasses" value="true"/>
-      <property name="allowUndeclaredRTE" value="true"/>
+    <module name="LineLength">
+      <property name="max" value="100"/>
+      <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
     </module>
-
-    <module name="JavadocType">
-      <property name="scope" value="protected"/>
-      <property name="severity" value="error"/>
+    <module name="AvoidStarImport"/>
+    <module name="OneTopLevelClass"/>
+    <module name="NoLineWrap"/>
+    <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="JavadocStyle">
-      <property name="severity" value="warning"/>
+    <module name="NeedBraces"/>
+    <module name="LeftCurly"/>
+    <module name="RightCurly">
+      <property name="id" value="RightCurlySame"/>
+      <property name="tokens"
+          value="LITERAL_TRY, LITERAL_CATCH, LITERAL_FINALLY, LITERAL_IF, LITERAL_ELSE,
+                    LITERAL_DO"/>
     </module>
-
-    <!--
-
-    NAMING CHECKS
-
-    -->
-
-    <!-- Item 38 - Adhere to generally accepted naming conventions -->
-
-    <module name="PackageName">
-      <!-- Validates identifiers for package names against the
-        supplied expression. -->
-      <!-- Here the default checkstyle rule restricts package name parts to
-        seven characters, this is not in line with common practice at Google.
-      -->
-      <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]{1,})*$"/>
-      <property name="severity" value="warning"/>
+    <module name="RightCurly">
+      <property name="id" value="RightCurlyAlone"/>
+      <property name="option" value="alone"/>
+      <property name="tokens"
+          value="CLASS_DEF, METHOD_DEF, CTOR_DEF, LITERAL_FOR, LITERAL_WHILE, STATIC_INIT,
+                    INSTANCE_INIT"/>
     </module>
-
-    <module name="TypeNameCheck">
-      <!-- Validates static, final fields against the
-      expression "^[A-Z][a-zA-Z0-9]*$". -->
-      <metadata name="altname" value="TypeName"/>
-      <property name="severity" value="warning"/>
+    <module name="WhitespaceAround">
+      <property name="allowEmptyConstructors" value="true"/>
+      <property name="allowEmptyLambdas" 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="ConstantNameCheck">
-      <!-- Validates non-private, static, final fields against the supplied
-      public/package final fields "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$". -->
-      <metadata name="altname" value="ConstantName"/>
-      <property name="applyToPublic" value="true"/>
-      <property name="applyToProtected" value="true"/>
-      <property name="applyToPackage" value="true"/>
-      <property name="applyToPrivate" value="false"/>
-      <property name="format" value="^([A-Z][A-Z0-9]*(_[A-Z0-9]+)*|FLAG_.*)$"/>
-      <message key="name.invalidPattern"
-               value="Variable ''{0}'' should be in ALL_CAPS (if it is a constant) or be private (otherwise)."/>
-      <property name="severity" value="warning"/>
+    <module name="OneStatementPerLine"/>
+    <module name="MultipleVariableDeclarations"/>
+    <module name="ArrayTypeStyle"/>
+    <module name="MissingSwitchDefault"/>
+    <module name="FallThrough"/>
+    <module name="UpperEll"/>
+    <module name="ModifierOrder"/>
+    <module name="EmptyLineSeparator">
+      <property name="allowNoEmptyLineBetweenFields" value="true"/>
     </module>
-
-    <module name="StaticVariableNameCheck">
-      <!-- Validates static, non-final fields against the supplied
-      expression "^[a-z][a-zA-Z0-9]*_?$". -->
-      <metadata name="altname" value="StaticVariableName"/>
-      <property name="applyToPublic" value="true"/>
-      <property name="applyToProtected" value="true"/>
-      <property name="applyToPackage" value="true"/>
-      <property name="applyToPrivate" value="true"/>
-      <property name="format" value="^[a-z][a-zA-Z0-9]*_?$"/>
-      <property name="severity" value="warning"/>
+    <module name="SeparatorWrap">
+      <property name="id" value="SeparatorWrapDot"/>
+      <property name="tokens" value="DOT"/>
+      <property name="option" value="nl"/>
     </module>
-
-    <module name="MemberNameCheck">
-      <!-- Validates non-static members against the supplied expression. -->
-      <metadata name="altname" value="MemberName"/>
-      <property name="applyToPublic" value="true"/>
-      <property name="applyToProtected" value="true"/>
-      <property name="applyToPackage" value="true"/>
-      <property name="applyToPrivate" value="true"/>
-      <property name="format" value="^[a-z][a-zA-Z0-9]*$"/>
-      <property name="severity" value="warning"/>
+    <module name="SeparatorWrap">
+      <property name="id" value="SeparatorWrapComma"/>
+      <property name="tokens" value="COMMA"/>
+      <property name="option" value="EOL"/>
     </module>
-
-    <module name="MethodNameCheck">
-      <!-- Validates identifiers for method names. -->
-      <metadata name="altname" value="MethodName"/>
-      <property name="format" value="^[a-z][a-zA-Z0-9]*(_[a-zA-Z0-9]+)*$"/>
-      <property name="severity" value="warning"/>
+    <module name="SeparatorWrap">
+      <!-- ELLIPSIS is EOL until https://github.com/google/styleguide/issues/258 -->
+      <property name="id" value="SeparatorWrapEllipsis"/>
+      <property name="tokens" value="ELLIPSIS"/>
+      <property name="option" value="EOL"/>
     </module>
-
-    <module name="ParameterName">
-      <!-- Validates identifiers for method parameters against the
-        expression "^[a-z][a-zA-Z0-9]*$". -->
-      <property name="severity" value="warning"/>
+    <module name="SeparatorWrap">
+      <!-- ARRAY_DECLARATOR is EOL until https://github.com/google/styleguide/issues/259 -->
+      <property name="id" value="SeparatorWrapArrayDeclarator"/>
+      <property name="tokens" value="ARRAY_DECLARATOR"/>
+      <property name="option" value="EOL"/>
     </module>
-
-    <module name="LocalFinalVariableName">
-      <!-- Validates identifiers for local final variables against the
-        expression "^[a-z][a-zA-Z0-9]*$". -->
-      <property name="severity" value="warning"/>
+    <module name="SeparatorWrap">
+      <property name="id" value="SeparatorWrapMethodRef"/>
+      <property name="tokens" value="METHOD_REF"/>
+      <property name="option" value="nl"/>
     </module>
-
-    <module name="LocalVariableName">
-      <!-- Validates identifiers for local variables against the
-        expression "^[a-z][a-zA-Z0-9]*$". -->
-      <property name="severity" value="warning"/>
+    <module name="PackageName">
+      <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]*)*$"/>
+      <message key="name.invalidPattern"
+          value="Package name ''{0}'' must match pattern ''{1}''."/>
     </module>
-
-
-    <!--
-
-    LENGTH and CODING CHECKS
-
-    -->
-
-    <module name="LineLength">
-      <!-- Checks if a line is too long. -->
-      <property name="max" value="${com.puppycrawl.tools.checkstyle.checks.sizes.LineLength.max}" default="100"/>
-      <property name="severity" value="error"/>
-
-      <!--
-        The default ignore pattern exempts the following elements:
-          - import statements
-          - long URLs inside comments
-      -->
-
-      <property name="ignorePattern"
-          value="${com.puppycrawl.tools.checkstyle.checks.sizes.LineLength.ignorePattern}"
-          default="^(package .*;\s*)|(import .*;\s*)|( *(\*|//).*https?://.*)$"/>
+    <module name="TypeName">
+      <message key="name.invalidPattern"
+          value="Type name ''{0}'' must match pattern ''{1}''."/>
     </module>
-
-    <module name="LeftCurly">
-      <!-- Checks for placement of the left curly brace ('{'). -->
-      <property name="severity" value="warning"/>
+    <module name="MemberName">
+      <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9]*$"/>
+      <message key="name.invalidPattern"
+          value="Member name ''{0}'' must match pattern ''{1}''."/>
     </module>
-
-    <module name="RightCurly">
-      <!-- Checks right curlies on CATCH, ELSE, and TRY blocks are on
-      the same line. e.g., the following example is fine:
-      <pre>
-        if {
-          ...
-        } else
-      </pre>
-      -->
-      <!-- This next example is not fine:
-      <pre>
-        if {
-          ...
-        }
-        else
-      </pre>
-      -->
-      <property name="option" value="same"/>
-      <property name="severity" value="warning"/>
+    <module name="ParameterName">
+      <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
+      <message key="name.invalidPattern"
+          value="Parameter name ''{0}'' must match pattern ''{1}''."/>
     </module>
-
-    <!-- Checks for braces around if and else blocks -->
-    <module name="NeedBraces">
-      <property name="severity" value="warning"/>
-      <property name="tokens" value="LITERAL_IF, LITERAL_ELSE, LITERAL_FOR, LITERAL_WHILE, LITERAL_DO"/>
+    <module name="LambdaParameterName">
+      <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
+      <message key="name.invalidPattern"
+          value="Lambda parameter name ''{0}'' must match pattern ''{1}''."/>
     </module>
-
-    <module name="UpperEll">
-      <!-- Checks that long constants are defined with an upper ell.-->
-      <property name="severity" value="error"/>
+    <module name="CatchParameterName">
+      <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
+      <message key="name.invalidPattern"
+          value="Catch parameter name ''{0}'' must match pattern ''{1}''."/>
     </module>
-
-    <module name="FallThrough">
-      <!-- Warn about falling through to the next case statement.  Similar to
-      javac -Xlint:fallthrough, but the check is suppressed if a single-line comment
-      on the last non-blank line preceding the fallen-into case contains 'fall through' (or
-      some other variants which we don't publicized to promote consistency).
-      -->
-      <property name="reliefPattern"
-       value="fall through|Fall through|fallthru|Fallthru|falls through|Falls through|fallthrough|Fallthrough|No break|NO break|no break|continue on"/>
-      <property name="severity" value="error"/>
+    <module name="LocalVariableName">
+      <property name="tokens" value="VARIABLE_DEF"/>
+      <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
+      <message key="name.invalidPattern"
+          value="Local variable name ''{0}'' must match pattern ''{1}''."/>
     </module>
-
-
-    <!--
-
-    MODIFIERS CHECKS
-
-    -->
-
-    <module name="ModifierOrder">
-      <!-- Warn if modifier order is inconsistent with JLS3 8.1.1, 8.3.1, and
-           8.4.3.  The prescribed order is:
-           public, protected, private, abstract, static, final, transient, volatile,
-           synchronized, native, strictfp
-        -->
+    <module name="ClassTypeParameterName">
+      <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
+      <message key="name.invalidPattern"
+          value="Class type name ''{0}'' must match pattern ''{1}''."/>
     </module>
-
-
-    <!--
-
-    WHITESPACE CHECKS
-
-    -->
-
-    <module name="WhitespaceAround">
-      <!-- Checks that various tokens are surrounded by whitespace.
-           This includes most binary operators and keywords followed
-           by regular or curly braces.
-      -->
-      <property name="tokens" value="ASSIGN, BAND, BAND_ASSIGN, BOR,
-        BOR_ASSIGN, BSR, BSR_ASSIGN, BXOR, BXOR_ASSIGN, COLON, DIV, DIV_ASSIGN,
-        EQUAL, GE, GT, LAND, LE, LITERAL_CATCH, LITERAL_DO, LITERAL_ELSE,
-        LITERAL_FINALLY, LITERAL_FOR, LITERAL_IF, LITERAL_RETURN,
-        LITERAL_SYNCHRONIZED, LITERAL_TRY, LITERAL_WHILE, LOR, LT, MINUS,
-        MINUS_ASSIGN, MOD, MOD_ASSIGN, NOT_EQUAL, PLUS, PLUS_ASSIGN, QUESTION,
-        SL, SL_ASSIGN, SR_ASSIGN, STAR, STAR_ASSIGN"/>
-      <property name="severity" value="error"/>
+    <module name="MethodTypeParameterName">
+      <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
+      <message key="name.invalidPattern"
+          value="Method type name ''{0}'' must match pattern ''{1}''."/>
     </module>
-
-    <module name="WhitespaceAfter">
-      <!-- Checks that commas, semicolons and typecasts are followed by
-           whitespace.
-      -->
-      <property name="tokens" value="COMMA, SEMI, TYPECAST"/>
+    <module name="InterfaceTypeParameterName">
+      <property name="format" value="(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)"/>
+      <message key="name.invalidPattern"
+          value="Interface type name ''{0}'' must match pattern ''{1}''."/>
     </module>
-
-    <module name="NoWhitespaceAfter">
-      <!-- Checks that there is no whitespace after various unary operators.
-           Linebreaks are allowed.
-      -->
-      <property name="tokens" value="BNOT, DEC, DOT, INC, LNOT, UNARY_MINUS,
-        UNARY_PLUS"/>
-      <property name="allowLineBreaks" value="true"/>
-      <property name="severity" value="error"/>
+    <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="Indentation">
+      <property name="basicOffset" value="2"/>
+      <property name="braceAdjustment" value="0"/>
+      <property name="caseIndent" value="2"/>
+      <property name="throwsIndent" value="4"/>
+      <property name="lineWrappingIndentation" value="4"/>
+      <property name="arrayInitIndent" value="2"/>
+    </module>
+    <module name="AbbreviationAsWordInName">
+      <property name="ignoreFinal" value="false"/>
+      <property name="allowedAbbreviationLength" value="1"/>
+    </module>
+    <module name="OverloadMethodsDeclarationOrder"/>
+    <module name="VariableDeclarationUsageDistance"/>
+    <module name="CustomImportOrder">
+      <property name="sortImportsInGroupAlphabetically" value="true"/>
+      <property name="separateLineBetweenGroups" value="true"/>
+      <property name="customImportOrderRules" value="STATIC###THIRD_PARTY_PACKAGE"/>
+    </module>
+    <module name="MethodParamPad"/>
     <module name="NoWhitespaceBefore">
-      <!-- Checks that there is no whitespace before various unary operators.
-           Linebreaks are allowed.
-      -->
-      <property name="tokens" value="SEMI, DOT, POST_DEC, POST_INC"/>
+      <property name="tokens"
+          value="COMMA, SEMI, POST_INC, POST_DEC, DOT, ELLIPSIS, METHOD_REF"/>
       <property name="allowLineBreaks" value="true"/>
-      <property name="severity" value="error"/>
     </module>
-
-    <module name="ParenPad">
-      <!-- Checks that there is no whitespace before close parens or after
-           open parens.
-      -->
-      <property name="severity" value="warning"/>
+    <module name="ParenPad"/>
+    <module name="OperatorWrap">
+      <property name="option" value="NL"/>
+      <property name="tokens"
+          value="BAND, BOR, BSR, BXOR, DIV, EQUAL, GE, GT, LAND, LE, LITERAL_INSTANCEOF, LOR,
+                    LT, MINUS, MOD, NOT_EQUAL, PLUS, QUESTION, SL, SR, STAR, METHOD_REF "/>
     </module>
-
+    <module name="AnnotationLocation">
+      <property name="id" value="AnnotationLocationMostCases"/>
+      <property name="tokens"
+          value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF"/>
+    </module>
+    <module name="AnnotationLocation">
+      <property name="id" value="AnnotationLocationVariables"/>
+      <property name="tokens" value="VARIABLE_DEF"/>
+      <property name="allowSamelineMultipleAnnotations" value="true"/>
+    </module>
+    <module name="NonEmptyAtclauseDescription"/>
+    <module name="InvalidJavadocPosition"/>
+    <module name="JavadocTagContinuationIndentation"/>
+    <module name="SummaryJavadoc">
+      <property name="forbiddenSummaryFragments"
+          value="^@return the *|^This method returns |^A [{]@code [a-zA-Z0-9]+[}]( is a )"/>
+    </module>
+    <module name="JavadocParagraph"/>
+    <module name="AtclauseOrder">
+      <property name="tagOrder" value="@param, @return, @throws, @deprecated"/>
+      <property name="target"
+          value="CLASS_DEF, INTERFACE_DEF, ENUM_DEF, METHOD_DEF, CTOR_DEF, VARIABLE_DEF"/>
+    </module>
+    <module name="JavadocMethod">
+      <property name="scope" value="public"/>
+      <property name="allowMissingParamTags" value="true"/>
+      <property name="allowMissingThrowsTags" value="true"/>
+      <property name="allowMissingReturnTag" value="true"/>
+      <property name="allowedAnnotations" value="Override, Test"/>
+      <property name="allowThrowsTagsForSubclasses" value="true"/>
+    </module>
+    <module name="MissingJavadocMethod">
+      <property name="scope" value="public"/>
+      <property name="minLineCount" value="2"/>
+      <property name="allowedAnnotations" value="Override, Test"/>
+    </module>
+    <module name="MethodName">
+      <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9_]*$"/>
+      <message key="name.invalidPattern"
+          value="Method name ''{0}'' must match pattern ''{1}''."/>
+    </module>
+    <module name="SingleLineJavadoc">
+      <property name="ignoreInlineTags" value="false"/>
+    </module>
+    <module name="EmptyCatchBlock">
+      <property name="exceptionVariableName" value="expected"/>
+    </module>
+    <module name="CommentsIndentation"/>
   </module>
 </module>
-
diff --git a/pom.xml b/pom.xml
index 3f296b7b7..2afa6b892 100644
--- a/pom.xml
+++ b/pom.xml
@@ -335,7 +335,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-checkstyle-plugin</artifactId>
-          <version>3.0.0</version>
+          <version>3.1.0</version>
         </plugin>
         <plugin>
           <groupId>org.codehaus.mojo</groupId>
@@ -448,22 +448,6 @@
           </execution>
         </executions>
       </plugin>
-      <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
-        <artifactId>maven-checkstyle-plugin</artifactId>
-        <configuration>
-          <configLocation>${project.root-directory}/checkstyle.xml</configLocation>
-          <consoleOutput>true</consoleOutput>
-          <suppressionsLocation>${project.root-directory}/checkstyle-suppressions.xml</suppressionsLocation>
-        </configuration>
-        <executions>
-          <execution>
-            <goals>
-              <goal>check</goal>
-            </goals>
-          </execution>
-        </executions>
-      </plugin>
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>findbugs-maven-plugin</artifactId>
@@ -622,6 +606,7 @@
         </plugins>
       </build>
     </profile>
+
     <!-- set project.root-directory property based on where we are -->
     <profile>
       <id>root-directory</id>
@@ -634,5 +619,40 @@
         <project.root-directory>.</project.root-directory>
       </properties>
     </profile>
+
+    <profile>
+      <!-- Only run checkstyle plugin on Java 8+ (checkstyle artifact only supports Java 8+) -->
+      <id>checkstyle-tests</id>
+      <activation>
+        <jdk>[1.8,)</jdk>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-checkstyle-plugin</artifactId>
+            <dependencies>
+              <dependency>
+                <groupId>com.puppycrawl.tools</groupId>
+                <artifactId>checkstyle</artifactId>
+                <version>8.23</version>
+              </dependency>
+            </dependencies>
+            <configuration>
+              <configLocation>checkstyle.xml</configLocation>
+              <consoleOutput>true</consoleOutput>
+              <suppressionsLocation>checkstyle-suppressions.xml</suppressionsLocation>
+            </configuration>
+            <executions>
+              <execution>
+                <goals>
+                  <goal>check</goal>
+                </goals>
+              </execution>
+            </executions>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
   </profiles>
 </project>
diff --git a/samples/checkstyle.xml b/samples/checkstyle.xml
deleted file mode 100644
index 66cd0c954..000000000
--- a/samples/checkstyle.xml
+++ /dev/null
@@ -1,336 +0,0 @@
-<?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">
-
-<!-- This is a checkstyle configuration file. For descriptions of
-what the following rules do, please see the checkstyle configuration
-page at http://checkstyle.sourceforge.net/config.html -->
-
-<module name="Checker">
-
-
-  <module name="RegexpSingleline">
-    <!-- Requires a Google copyright notice in each file.
-      Code intended to be open-sourced may have a multi-line copyright
-      notice, so that this required text appears on the second line:
-      <pre>
-        /*
-         * Copyright 2008 Google Inc.
-         *
-         * (details of open-source license...)
-      </pre>
-    -->
-    <property name="format"
-        value="^(//| \*) Copyright (\([cC]\) )?[\d]{4}(\-[\d]{4})? (Google Inc\.).*$" />
-    <property name="minimum" value="1" />
-    <property name="maximum" value="10" />
-    <property name="message" value="Google copyright is missing or malformed." />
-    <property name="severity" value="error" />
-  </module>
-
-  <module name="FileTabCharacter">
-    <!-- Checks that there are no tab characters in the file.
-    -->
-  </module>
-
-  <module name="NewlineAtEndOfFile"/>
-
-  <module name="RegexpSingleline">
-    <!-- Checks that FIXME is not used in comments.  TODO is preferred.
-    -->
-    <property name="format" value="((//.*)|(\*.*))FIXME" />
-    <property name="message" value='TODO is preferred to FIXME.  e.g. "TODO(johndoe): Refactor when v2 is released."' />
-  </module>
-
-  <module name="RegexpSingleline">
-    <!-- Checks that TODOs are named.  (Actually, just that they are followed
-         by an open paren.)
-    -->
-    <property name="format" value="((//.*)|(\*.*))TODO[^(]" />
-    <property name="message" value='All TODOs should be named.  e.g. "TODO(johndoe): Refactor when v2 is released."' />
-  </module>
-
-  <!-- All Java AST specific tests live under TreeWalker module. -->
-  <module name="TreeWalker">
-
-    <!--
-
-    IMPORT CHECKS
-
-    -->
-
-    <module name="RedundantImport">
-      <!-- Checks for redundant import statements. -->
-      <property name="severity" value="error"/>
-    </module>
-
-    <module name="ImportOrder">
-      <!-- Checks for out of order import statements. -->
-
-      <property name="severity" value="warning"/>
-      <property name="groups" value="com.google,android,junit,net,org,java,javax"/>
-      <!-- This ensures that static imports go first. -->
-      <property name="option" value="top"/>
-      <property name="tokens" value="STATIC_IMPORT, IMPORT"/>
-    </module>
-
-    <!--
-
-    JAVADOC CHECKS
-
-    -->
-
-    <!-- Checks for Javadoc comments.                     -->
-    <!-- See http://checkstyle.sf.net/config_javadoc.html -->
-    <module name="JavadocMethod">
-      <property name="scope" value="protected"/>
-      <property name="severity" value="warning"/>
-      <property name="allowMissingJavadoc" value="true"/>
-      <property name="allowMissingParamTags" value="true"/>
-      <property name="allowMissingReturnTag" value="true"/>
-      <property name="allowMissingThrowsTags" value="true"/>
-      <property name="allowThrowsTagsForSubclasses" value="true"/>
-      <property name="allowUndeclaredRTE" value="true"/>
-    </module>
-
-    <module name="JavadocType">
-      <property name="scope" value="protected"/>
-      <property name="severity" value="error"/>
-    </module>
-
-    <module name="JavadocStyle">
-      <property name="severity" value="warning"/>
-    </module>
-
-    <!--
-
-    NAMING CHECKS
-
-    -->
-
-    <!-- Item 38 - Adhere to generally accepted naming conventions -->
-
-    <module name="PackageName">
-      <!-- Validates identifiers for package names against the
-        supplied expression. -->
-      <!-- Here the default checkstyle rule restricts package name parts to
-        seven characters, this is not in line with common practice at Google.
-      -->
-      <property name="format" value="^[a-z]+(\.[a-z][a-z0-9]{1,})*$"/>
-      <property name="severity" value="warning"/>
-    </module>
-
-    <module name="TypeNameCheck">
-      <!-- Validates static, final fields against the
-      expression "^[A-Z][a-zA-Z0-9]*$". -->
-      <metadata name="altname" value="TypeName"/>
-      <property name="severity" value="warning"/>
-    </module>
-
-    <module name="ConstantNameCheck">
-      <!-- Validates non-private, static, final fields against the supplied
-      public/package final fields "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$". -->
-      <metadata name="altname" value="ConstantName"/>
-      <property name="applyToPublic" value="true"/>
-      <property name="applyToProtected" value="true"/>
-      <property name="applyToPackage" value="true"/>
-      <property name="applyToPrivate" value="false"/>
-      <property name="format" value="^([A-Z][A-Z0-9]*(_[A-Z0-9]+)*|FLAG_.*)$"/>
-      <message key="name.invalidPattern"
-               value="Variable ''{0}'' should be in ALL_CAPS (if it is a constant) or be private (otherwise)."/>
-      <property name="severity" value="warning"/>
-    </module>
-
-    <module name="StaticVariableNameCheck">
-      <!-- Validates static, non-final fields against the supplied
-      expression "^[a-z][a-zA-Z0-9]*_?$". -->
-      <metadata name="altname" value="StaticVariableName"/>
-      <property name="applyToPublic" value="true"/>
-      <property name="applyToProtected" value="true"/>
-      <property name="applyToPackage" value="true"/>
-      <property name="applyToPrivate" value="true"/>
-      <property name="format" value="^[a-z][a-zA-Z0-9]*_?$"/>
-      <property name="severity" value="warning"/>
-    </module>
-
-    <module name="MemberNameCheck">
-      <!-- Validates non-static members against the supplied expression. -->
-      <metadata name="altname" value="MemberName"/>
-      <property name="applyToPublic" value="true"/>
-      <property name="applyToProtected" value="true"/>
-      <property name="applyToPackage" value="true"/>
-      <property name="applyToPrivate" value="true"/>
-      <property name="format" value="^[a-z][a-zA-Z0-9]*$"/>
-      <property name="severity" value="warning"/>
-    </module>
-
-    <module name="MethodNameCheck">
-      <!-- Validates identifiers for method names. -->
-      <metadata name="altname" value="MethodName"/>
-      <property name="format" value="^[a-z][a-zA-Z0-9]*(_[a-zA-Z0-9]+)*$"/>
-      <property name="severity" value="warning"/>
-    </module>
-
-    <module name="ParameterName">
-      <!-- Validates identifiers for method parameters against the
-        expression "^[a-z][a-zA-Z0-9]*$". -->
-      <property name="severity" value="warning"/>
-    </module>
-
-    <module name="LocalFinalVariableName">
-      <!-- Validates identifiers for local final variables against the
-        expression "^[a-z][a-zA-Z0-9]*$". -->
-      <property name="severity" value="warning"/>
-    </module>
-
-    <module name="LocalVariableName">
-      <!-- Validates identifiers for local variables against the
-        expression "^[a-z][a-zA-Z0-9]*$". -->
-      <property name="severity" value="warning"/>
-    </module>
-
-
-    <!--
-
-    LENGTH and CODING CHECKS
-
-    -->
-
-    <module name="LineLength">
-      <!-- Checks if a line is too long. -->
-      <property name="max" value="${com.puppycrawl.tools.checkstyle.checks.sizes.LineLength.max}" default="100"/>
-      <property name="severity" value="error"/>
-
-      <!--
-        The default ignore pattern exempts the following elements:
-          - import statements
-          - long URLs inside comments
-      -->
-
-      <property name="ignorePattern"
-          value="${com.puppycrawl.tools.checkstyle.checks.sizes.LineLength.ignorePattern}"
-          default="^(package .*;\s*)|(import .*;\s*)|( *\* *https?://.*)$"/>
-    </module>
-
-    <module name="LeftCurly">
-      <!-- Checks for placement of the left curly brace ('{'). -->
-      <property name="severity" value="warning"/>
-    </module>
-
-    <module name="RightCurly">
-      <!-- Checks right curlies on CATCH, ELSE, and TRY blocks are on
-      the same line. e.g., the following example is fine:
-      <pre>
-        if {
-          ...
-        } else
-      </pre>
-      -->
-      <!-- This next example is not fine:
-      <pre>
-        if {
-          ...
-        }
-        else
-      </pre>
-      -->
-      <property name="option" value="same"/>
-      <property name="severity" value="warning"/>
-    </module>
-
-    <!-- Checks for braces around if and else blocks -->
-    <module name="NeedBraces">
-      <property name="severity" value="warning"/>
-      <property name="tokens" value="LITERAL_IF, LITERAL_ELSE, LITERAL_FOR, LITERAL_WHILE, LITERAL_DO"/>
-    </module>
-
-    <module name="UpperEll">
-      <!-- Checks that long constants are defined with an upper ell.-->
-      <property name="severity" value="error"/>
-    </module>
-
-    <module name="FallThrough">
-      <!-- Warn about falling through to the next case statement.  Similar to
-      javac -Xlint:fallthrough, but the check is suppressed if a single-line comment
-      on the last non-blank line preceding the fallen-into case contains 'fall through' (or
-      some other variants which we don't publicized to promote consistency).
-      -->
-      <property name="reliefPattern"
-       value="fall through|Fall through|fallthru|Fallthru|falls through|Falls through|fallthrough|Fallthrough|No break|NO break|no break|continue on"/>
-      <property name="severity" value="error"/>
-    </module>
-
-
-    <!--
-
-    MODIFIERS CHECKS
-
-    -->
-
-    <module name="ModifierOrder">
-      <!-- Warn if modifier order is inconsistent with JLS3 8.1.1, 8.3.1, and
-           8.4.3.  The prescribed order is:
-           public, protected, private, abstract, static, final, transient, volatile,
-           synchronized, native, strictfp
-        -->
-    </module>
-
-
-    <!--
-
-    WHITESPACE CHECKS
-
-    -->
-
-    <module name="WhitespaceAround">
-      <!-- Checks that various tokens are surrounded by whitespace.
-           This includes most binary operators and keywords followed
-           by regular or curly braces.
-      -->
-      <property name="tokens" value="ASSIGN, BAND, BAND_ASSIGN, BOR,
-        BOR_ASSIGN, BSR, BSR_ASSIGN, BXOR, BXOR_ASSIGN, COLON, DIV, DIV_ASSIGN,
-        EQUAL, GE, GT, LAND, LE, LITERAL_CATCH, LITERAL_DO, LITERAL_ELSE,
-        LITERAL_FINALLY, LITERAL_FOR, LITERAL_IF, LITERAL_RETURN,
-        LITERAL_SYNCHRONIZED, LITERAL_TRY, LITERAL_WHILE, LOR, LT, MINUS,
-        MINUS_ASSIGN, MOD, MOD_ASSIGN, NOT_EQUAL, PLUS, PLUS_ASSIGN, QUESTION,
-        SL, SL_ASSIGN, SR_ASSIGN, STAR, STAR_ASSIGN"/>
-      <property name="severity" value="error"/>
-    </module>
-
-    <module name="WhitespaceAfter">
-      <!-- Checks that commas, semicolons and typecasts are followed by
-           whitespace.
-      -->
-      <property name="tokens" value="COMMA, SEMI, TYPECAST"/>
-    </module>
-
-    <module name="NoWhitespaceAfter">
-      <!-- Checks that there is no whitespace after various unary operators.
-           Linebreaks are allowed.
-      -->
-      <property name="tokens" value="BNOT, DEC, DOT, INC, LNOT, UNARY_MINUS,
-        UNARY_PLUS"/>
-      <property name="allowLineBreaks" value="true"/>
-      <property name="severity" value="error"/>
-    </module>
-
-    <module name="NoWhitespaceBefore">
-      <!-- Checks that there is no whitespace before various unary operators.
-           Linebreaks are allowed.
-      -->
-      <property name="tokens" value="SEMI, DOT, POST_DEC, POST_INC"/>
-      <property name="allowLineBreaks" value="true"/>
-      <property name="severity" value="error"/>
-    </module>
-
-    <module name="ParenPad">
-      <!-- Checks that there is no whitespace before close parens or after
-           open parens.
-      -->
-      <property name="severity" value="warning"/>
-    </module>
-
-  </module>
-</module>
-
diff --git a/samples/dailymotion-simple-cmdline-sample/pom.xml b/samples/dailymotion-simple-cmdline-sample/pom.xml
index 8c5ca35fb..c7977fc01 100644
--- a/samples/dailymotion-simple-cmdline-sample/pom.xml
+++ b/samples/dailymotion-simple-cmdline-sample/pom.xml
@@ -33,23 +33,6 @@
           </systemProperties>
         </configuration>
       </plugin>
-      <plugin>
-        <artifactId>maven-checkstyle-plugin</artifactId>
-        <version>3.0.0</version>
-        <configuration>
-          <configLocation>../../checkstyle.xml</configLocation>
-          <consoleOutput>true</consoleOutput>
-          <failOnViolation>false</failOnViolation>
-          <suppressionsLocation>../../checkstyle-suppressions.xml</suppressionsLocation>
-        </configuration>
-        <executions>
-          <execution>
-            <goals>
-              <goal>check</goal>
-            </goals>
-          </execution>
-        </executions>
-      </plugin>
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>findbugs-maven-plugin</artifactId>
@@ -95,4 +78,41 @@
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   </properties>
+
+  <profiles>
+    <profile>
+      <!-- Only run checkstyle plugin on Java 8+ (checkstyle artifact only supports Java 8+) -->
+      <id>checkstyle-tests</id>
+      <activation>
+        <jdk>[1.8,)</jdk>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-checkstyle-plugin</artifactId>
+            <dependencies>
+              <dependency>
+                <groupId>com.puppycrawl.tools</groupId>
+                <artifactId>checkstyle</artifactId>
+                <version>8.23</version>
+              </dependency>
+            </dependencies>
+            <configuration>
+              <configLocation>../../checkstyle.xml</configLocation>
+              <consoleOutput>true</consoleOutput>
+              <suppressionsLocation>../../checkstyle-suppressions.xml</suppressionsLocation>
+            </configuration>
+            <executions>
+              <execution>
+                <goals>
+                  <goal>check</goal>
+                </goals>
+              </execution>
+            </executions>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
+  </profiles>
 </project>

From 1db4a5646b6fc4831ccbb7402aa0c9dd4b1c8013 Mon Sep 17 00:00:00 2001
From: Jeff Ching <chingor@google.com>
Date: Thu, 8 Aug 2019 10:48:34 -0700
Subject: [PATCH 2/2] Modify checkstyle rule to adhere to google-java-format

---
 checkstyle.xml | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/checkstyle.xml b/checkstyle.xml
index 734575e4c..d7917523a 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -68,7 +68,8 @@
     </module>
     <module name="RightCurly">
       <property name="id" value="RightCurlyAlone"/>
-      <property name="option" value="alone"/>
+      <!-- alone -> alone_or_singleine: google-java-format converts to this style -->
+      <property name="option" value="alone_or_singleline"/>
       <property name="tokens"
           value="CLASS_DEF, METHOD_DEF, CTOR_DEF, LITERAL_FOR, LITERAL_WHILE, STATIC_INIT,
                     INSTANCE_INIT"/>
@@ -255,9 +256,10 @@
       <message key="name.invalidPattern"
           value="Method name ''{0}'' must match pattern ''{1}''."/>
     </module>
-    <module name="SingleLineJavadoc">
-      <property name="ignoreInlineTags" value="false"/>
-    </module>
+    <!-- Ignore SingleLineJavadoc rule: google-java-format converts to this style -->
+    <!--<module name="SingleLineJavadoc">-->
+      <!--<property name="ignoreInlineTags" value="false"/>-->
+    <!--</module>-->
     <module name="EmptyCatchBlock">
       <property name="exceptionVariableName" value="expected"/>
     </module>