Enable Checkstyle 7.7.

checkstyle.xml

@@ -1,9 +1,10 @@
 <?xml version="1.0"?>
 <!DOCTYPE module PUBLIC
-    "-//Puppy Crawl//DTD Check Configuration 1.2//EN"
+    "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
-    "http://www.puppycrawl.com/dtds/configuration_1_2.dtd">
+    "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
 
 <module name="Checker">
+  <module name="SuppressWarningsFilter"/>
   <module name="NewlineAtEndOfFile"/>
   <module name="FileLength"/>
   <module name="FileTabCharacter"/>
@@ -44,7 +45,7 @@
     <module name="LocalVariableName"/>
     <module name="MemberName"/>
     <module name="MethodName"/>
-    <module name="PackageName"/>
+    <!--<module name="PackageName"/>-->
     <module name="ParameterName"/>
     <module name="StaticVariableName"/>
     <module name="TypeName"/>
@@ -56,7 +57,9 @@
     <module name="IllegalImport"/>
     <!-- defaults to sun.* packages -->
     <module name="RedundantImport"/>
-    <module name="UnusedImports"/>
+    <module name="UnusedImports">
+      <property name="processJavadoc" value="true"/>
+    </module>
 
 
     <!-- Checks for Size Violations.                    -->
@@ -64,7 +67,9 @@
     <module name="LineLength">
       <property name="max" value="100"/>
     </module>
-    <module name="MethodLength"/>
+    <module name="MethodLength">
+      <property name="max" value="200"/>
+    </module>
 
 
     <!-- Checks for whitespace                               -->
@@ -78,7 +83,15 @@
     <module name="ParenPad"/>
     <module name="TypecastParenPad"/>
     <module name="WhitespaceAfter"/>
-    <module name="WhitespaceAround"/>
+    <module name="WhitespaceAround">
+      <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_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, SLIST,
+          SL_ASSIGN, SR, SR_ASSIGN, STAR, STAR_ASSIGN, LITERAL_ASSERT, TYPE_EXTENSION_AND"/>
+    </module>
 
 
     <!-- Modifier Checks                                    -->
@@ -108,7 +121,7 @@
     <!--module name="InnerAssignment"/-->
     <!--module name="MagicNumber"/-->
     <!--module name="MissingSwitchDefault"/-->
-    <module name="RedundantThrows"/>
+    <!--<module name="RedundantThrows"/>-->
     <module name="SimplifyBooleanExpression"/>
     <module name="SimplifyBooleanReturn"/>
 
@@ -127,5 +140,8 @@
     <!--module name="FinalParameters"/-->
     <!--module name="TodoComment"/-->
     <module name="UpperEll"/>
+
+    <!-- Make the @SuppressWarnings annotations available to Checkstyle -->
+    <module name="SuppressWarningsHolder"/>
   </module>
 </module>

examples/src/main/java/com/squareup/moshi/recipes/FromJsonWithoutStrings.java

@@ -44,6 +44,7 @@ public final class FromJsonWithoutStrings {
     new FromJsonWithoutStrings().run();
   }
 
+  @SuppressWarnings("checkstyle:membername")
   private static final class EventJson {
     String title;
     String begin_date;
@@ -55,10 +56,10 @@ public final class FromJsonWithoutStrings {
     String beginDateAndTime;
 
     @Override public String toString() {
-      return "Event{" +
+      return "Event{"
-          "title='" + title + '\'' +
+          + "title='" + title + '\''
-          ", beginDateAndTime='" + beginDateAndTime + '\'' +
+          + ", beginDateAndTime='" + beginDateAndTime + '\''
-          '}';
+          + '}';
     }
   }
 

examples/src/main/java/com/squareup/moshi/recipes/Unwrap.java

@@ -32,6 +32,9 @@ import java.util.Set;
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
 
 final class Unwrap {
+  private Unwrap() {
+  }
+
   public static void main(String[] args) throws Exception {
     String json = ""
         + "{\"data\":"

examples/src/main/java/com/squareup/moshi/recipes/models/BlackjackHand.java

@@ -17,13 +17,14 @@ package com.squareup.moshi.recipes.models;
 
 import java.util.List;
 
+@SuppressWarnings("checkstyle:membername")
 public final class BlackjackHand {
   public final Card hidden_card;
   public final List<Card> visible_cards;
 
-  public BlackjackHand(Card hidden_card, List<Card> visible_cards) {
+  public BlackjackHand(Card hiddenCard, List<Card> visibleCards) {
-    this.hidden_card = hidden_card;
+    this.hidden_card = hiddenCard;
-    this.visible_cards = visible_cards;
+    this.visible_cards = visibleCards;
   }
 
   @Override public String toString() {

moshi/src/main/java/com/squareup/moshi/AdapterMethodsFactory.java

@@ -31,7 +31,7 @@ final class AdapterMethodsFactory implements JsonAdapter.Factory {
   private final List<AdapterMethod> toAdapters;
   private final List<AdapterMethod> fromAdapters;
 
-  public AdapterMethodsFactory(List<AdapterMethod> toAdapters, List<AdapterMethod> fromAdapters) {
+  AdapterMethodsFactory(List<AdapterMethod> toAdapters, List<AdapterMethod> fromAdapters) {
     this.toAdapters = toAdapters;
     this.fromAdapters = fromAdapters;
   }
@@ -271,7 +271,7 @@ final class AdapterMethodsFactory implements JsonAdapter.Factory {
     return null;
   }
 
-  static abstract class AdapterMethod {
+  abstract static class AdapterMethod {
     final Type type;
     final Set<? extends Annotation> annotations;
     final Object adapter;
@@ -280,7 +280,7 @@ final class AdapterMethodsFactory implements JsonAdapter.Factory {
     final JsonAdapter<?>[] jsonAdapters;
     final boolean nullable;
 
-    public AdapterMethod(Type type, Set<? extends Annotation> annotations, Object adapter,
+    AdapterMethod(Type type, Set<? extends Annotation> annotations, Object adapter,
         Method method, int parameterCount, int adaptersOffset, boolean nullable) {
       this.type = Types.canonicalize(type);
       this.annotations = annotations;

moshi/src/main/java/com/squareup/moshi/ClassJsonAdapter.java

@@ -194,7 +194,7 @@ final class ClassJsonAdapter<T> extends JsonAdapter<T> {
     final Field field;
     final JsonAdapter<T> adapter;
 
-    public FieldBinding(String name, Field field, JsonAdapter<T> adapter) {
+    FieldBinding(String name, Field field, JsonAdapter<T> adapter) {
       this.name = name;
       this.field = field;
       this.adapter = adapter;

moshi/src/main/java/com/squareup/moshi/JsonReader.java

@@ -182,7 +182,7 @@ public abstract class JsonReader implements Closeable {
   final String[] pathNames = new String[32];
   final int[] pathIndices = new int[32];
 
-  /** True to accept non-spec compliant JSON */
+  /** True to accept non-spec compliant JSON. */
   boolean lenient;
 
   /** True to throw a {@link JsonDataException} on any attempt to call {@link #skipValue()}. */

moshi/src/main/java/com/squareup/moshi/JsonScope.java

@@ -17,6 +17,8 @@ package com.squareup.moshi;
 
 /** Lexical scoping elements within a JSON reader or writer. */
 final class JsonScope {
+  private JsonScope() {
+  }
 
   /** An array with no elements requires no separators or newlines before it is closed. */
   static final int EMPTY_ARRAY = 1;

moshi/src/main/java/com/squareup/moshi/JsonValueReader.java

@@ -50,7 +50,7 @@ final class JsonValueReader extends JsonReader {
 
   private final Object[] stack = new Object[32];
 
-  public JsonValueReader(Object root) {
+  JsonValueReader(Object root) {
     scopes[stackSize] = JsonScope.NONEMPTY_DOCUMENT;
     stack[stackSize++] = root;
   }

moshi/src/main/java/com/squareup/moshi/LinkedHashTreeMap.java

@@ -55,7 +55,7 @@ final class LinkedHashTreeMap<K, V> extends AbstractMap<K, V> implements Seriali
    * Create a natural order, empty tree map whose keys must be mutually
    * comparable and non-null.
    */
-  public LinkedHashTreeMap() {
+  LinkedHashTreeMap() {
     this(null);
   }
 
@@ -66,8 +66,10 @@ final class LinkedHashTreeMap<K, V> extends AbstractMap<K, V> implements Seriali
    * @param comparator the comparator to order elements with, or {@code null} to
    *     use the natural ordering.
    */
-  @SuppressWarnings({ "unchecked", "rawtypes" }) // unsafe! if comparator is null, this assumes K is comparable
+  @SuppressWarnings({
-  public LinkedHashTreeMap(Comparator<? super K> comparator) {
+      "unchecked", "rawtypes" // Unsafe! if comparator is null, this assumes K is comparable.
+  })
+  LinkedHashTreeMap(Comparator<? super K> comparator) {
     this.comparator = comparator != null
         ? comparator
         : (Comparator) NATURAL_ORDER;
@@ -473,14 +475,14 @@ final class LinkedHashTreeMap<K, V> extends AbstractMap<K, V> implements Seriali
     V value;
     int height;
 
-    /** Create the header entry */
+    /** Create the header entry. */
     Node() {
       key = null;
       hash = -1;
       next = prev = this;
     }
 
-    /** Create a regular entry */
+    /** Create a regular entry. */
     Node(Node<K, V> parent, K key, int hash, Node<K, V> next, Node<K, V> prev) {
       this.parent = parent;
       this.key = key;
@@ -665,7 +667,7 @@ final class LinkedHashTreeMap<K, V> extends AbstractMap<K, V> implements Seriali
    * comparisons. Using this class to create a tree of size <i>S</i> is
    * {@code O(S)}.
    */
-  final static class AvlBuilder<K, V> {
+  static final class AvlBuilder<K, V> {
     /** This stack is a singly linked list, linked by the 'parent' field. */
     private Node<K, V> stack;
     private int leavesToSkip;

moshi/src/main/java/com/squareup/moshi/MapJsonAdapter.java

@@ -41,7 +41,7 @@ final class MapJsonAdapter<K, V> extends JsonAdapter<Map<K, V>> {
   private final JsonAdapter<K> keyAdapter;
   private final JsonAdapter<V> valueAdapter;
 
-  public MapJsonAdapter(Moshi moshi, Type keyType, Type valueType) {
+  MapJsonAdapter(Moshi moshi, Type keyType, Type valueType) {
     this.keyAdapter = moshi.adapter(keyType);
     this.valueAdapter = moshi.adapter(valueType);
   }

moshi/src/main/java/com/squareup/moshi/StandardJsonAdapters.java

@@ -24,6 +24,9 @@ import java.util.Map;
 import java.util.Set;
 
 final class StandardJsonAdapters {
+  private StandardJsonAdapters() {
+  }
+
   public static final JsonAdapter.Factory FACTORY = new JsonAdapter.Factory() {
     @Override public JsonAdapter<?> create(
         Type type, Set<? extends Annotation> annotations, Moshi moshi) {
@@ -216,7 +219,7 @@ final class StandardJsonAdapters {
     private final T[] constants;
     private final JsonReader.Options options;
 
-    public EnumJsonAdapter(Class<T> enumType) {
+    EnumJsonAdapter(Class<T> enumType) {
       this.enumType = enumType;
       try {
         constants = enumType.getEnumConstants();
@@ -264,7 +267,7 @@ final class StandardJsonAdapters {
   static final class ObjectJsonAdapter extends JsonAdapter<Object> {
     private final Moshi moshi;
 
-    public ObjectJsonAdapter(Moshi moshi) {
+    ObjectJsonAdapter(Moshi moshi) {
       this.moshi = moshi;
     }
 

moshi/src/main/java/com/squareup/moshi/Types.java

@@ -560,7 +560,7 @@ public final class Types {
   private static final class GenericArrayTypeImpl implements GenericArrayType {
     private final Type componentType;
 
-    public GenericArrayTypeImpl(Type componentType) {
+    GenericArrayTypeImpl(Type componentType) {
       this.componentType = canonicalize(componentType);
     }
 
@@ -591,7 +591,7 @@ public final class Types {
     private final Type upperBound;
     private final Type lowerBound;
 
-    public WildcardTypeImpl(Type[] upperBounds, Type[] lowerBounds) {
+    WildcardTypeImpl(Type[] upperBounds, Type[] lowerBounds) {
       if (lowerBounds.length > 1) throw new IllegalArgumentException();
       if (upperBounds.length != 1) throw new IllegalArgumentException();
 

moshi/src/main/java/com/squareup/moshi/Util.java

@@ -25,6 +25,9 @@ import java.util.Set;
 final class Util {
   public static final Set<Annotation> NO_ANNOTATIONS = Collections.emptySet();
 
+  private Util() {
+  }
+
   public static boolean typesMatch(Type pattern, Type candidate) {
     // TODO: permit raw types (like Set.class) to match non-raw candidates (like Set<Long>).
     return pattern.equals(candidate);

pom.xml

@@ -127,6 +127,32 @@
     </pluginManagement>
 
     <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-checkstyle-plugin</artifactId>
+        <version>2.17</version>
+        <dependencies>
+          <dependency>
+            <groupId>com.puppycrawl.tools</groupId>
+            <artifactId>checkstyle</artifactId>
+            <version>7.7</version>
+          </dependency>
+        </dependencies>
+        <configuration>
+          <failsOnError>true</failsOnError>
+          <configLocation>checkstyle.xml</configLocation>
+          <consoleOutput>true</consoleOutput>
+          <excludes>**/Iso8601Utils.java</excludes>
+        </configuration>
+        <executions>
+          <execution>
+            <phase>verify</phase>
+            <goals>
+              <goal>checkstyle</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-release-plugin</artifactId>