[spike] use spotless to enforce/verify formatting conventions

pom.xml

@@ -75,6 +75,7 @@ We use these goals frequently to keep the dependencies and plugins up-to-date:
         <maven.release.version>3.1.1</maven.release.version>
         <maven.versions.version>2.18.0</maven.versions.version>
         <maven.surefire.version>3.5.2</maven.surefire.version>
+        <spotless.version>2.44.2</spotless.version>
         <maven.source.version>3.3.1</maven.source.version>
         <maven.exec.version>3.5.0</maven.exec.version>
         <moditect.version>1.2.2.Final</moditect.version>
@@ -134,6 +135,25 @@ We use these goals frequently to keep the dependencies and plugins up-to-date:
                 <artifactId>maven-install-plugin</artifactId>
                 <version>${maven.install.version}</version>
             </plugin>
+            <plugin>
+                <groupId>com.diffplug.spotless</groupId>
+                <artifactId>spotless-maven-plugin</artifactId>
+                <version>${spotless.version}</version>
+                <configuration>
+                    <java>
+                        <removeUnusedImports/>
+                        <importOrder/>
+                    </java>
+                </configuration>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>check</goal>
+                        </goals>
+                        <phase>compile</phase>
+                    </execution>
+                </executions>
+            </plugin>
         </plugins>
         <pluginManagement>
             <plugins>

vavr/src/main/java/io/vavr/$.java

@@ -18,14 +18,14 @@
  */
 package io.vavr;
 
+import io.vavr.collection.List;
+import io.vavr.concurrent.Future;
 import io.vavr.control.Either;
+import io.vavr.control.Option;
 import io.vavr.control.Try;
 import io.vavr.control.Validation;
 import io.vavr.match.annotation.Patterns;
 import io.vavr.match.annotation.Unapply;
-import io.vavr.collection.List;
-import io.vavr.concurrent.Future;
-import io.vavr.control.Option;
 
 /**
  * <strong>INTERNAL TYPE - turned to io.vavr.Patterns by vavr-match annotation processor.</strong>

vavr/src/main/java/io/vavr/CheckedConsumer.java

@@ -18,11 +18,11 @@
  */
 package io.vavr;
 
+import static io.vavr.CheckedConsumerModule.sneakyThrow;
+
 import java.util.Objects;
 import java.util.function.Consumer;
 
-import static io.vavr.CheckedConsumerModule.sneakyThrow;
-
 /**
  * A consumer that may throw, equivalent to {@linkplain java.util.function.Consumer}.
  *

vavr/src/main/java/io/vavr/CheckedPredicate.java

@@ -18,10 +18,10 @@
  */
 package io.vavr;
 
-import java.util.function.Predicate;
-
 import static io.vavr.CheckedPredicateModule.sneakyThrow;
 
+import java.util.function.Predicate;
+
 /**
  * A {@linkplain java.util.function.Predicate} which may throw.
  *

vavr/src/main/java/io/vavr/Lazy.java

@@ -22,7 +22,6 @@
 import io.vavr.collection.Seq;
 import io.vavr.collection.Vector;
 import io.vavr.control.Option;
-
 import java.io.IOException;
 import java.io.ObjectOutputStream;
 import java.io.Serializable;

vavr/src/main/java/io/vavr/PartialFunction.java

@@ -19,7 +19,6 @@
 package io.vavr;
 
 import io.vavr.control.Option;
-
 import java.util.function.Function;
 
 /**

vavr/src/main/java/io/vavr/Predicates.java

@@ -20,7 +20,6 @@
 
 import io.vavr.collection.Iterator;
 import io.vavr.collection.List;
-
 import java.util.Objects;
 import java.util.function.Predicate;
 

vavr/src/main/java/io/vavr/Value.java

@@ -18,6 +18,9 @@
  */
 package io.vavr;
 
+import static io.vavr.API.*;
+
+import io.vavr.collection.*;
 import io.vavr.collection.Array;
 import io.vavr.collection.CharSeq;
 import io.vavr.collection.HashMap;
@@ -27,7 +30,6 @@
 import io.vavr.collection.LinkedHashSet;
 import io.vavr.collection.List;
 import io.vavr.collection.Map;
-import io.vavr.collection.*;
 import io.vavr.collection.PriorityQueue;
 import io.vavr.collection.Queue;
 import io.vavr.collection.Set;
@@ -37,12 +39,10 @@
 import io.vavr.collection.TreeMap;
 import io.vavr.collection.TreeSet;
 import io.vavr.collection.Vector;
-import io.vavr.concurrent.Future;
 import io.vavr.control.Either;
 import io.vavr.control.Option;
 import io.vavr.control.Try;
 import io.vavr.control.Validation;
-
 import java.io.PrintStream;
 import java.io.PrintWriter;
 import java.util.*;
@@ -52,8 +52,6 @@
 import java.util.stream.Collector;
 import java.util.stream.StreamSupport;
 
-import static io.vavr.API.*;
-
 /**
  * Functional programming is all about values and transformation of values using functions. The {@code Value}
  * type reflects the values in a functional setting. It can be seen as the result of a partial function application.

vavr/src/main/java/io/vavr/collection/AbstractMultimap.java

@@ -18,18 +18,17 @@
  */
 package io.vavr.collection;
 
+import static io.vavr.API.Tuple;
+
 import io.vavr.Tuple;
 import io.vavr.Tuple2;
 import io.vavr.control.Option;
-
 import java.io.Serializable;
 import java.util.Collection;
 import java.util.Comparator;
 import java.util.Objects;
 import java.util.function.*;
 
-import static io.vavr.API.Tuple;
-
 /**
  * An {@link Multimap} implementation (not intended to be public).
  *

vavr/src/main/java/io/vavr/collection/AbstractQueue.java

@@ -21,7 +21,6 @@
 import io.vavr.Tuple;
 import io.vavr.Tuple2;
 import io.vavr.control.Option;
-
 import java.util.NoSuchElementException;
 import java.util.Objects;
 import java.util.function.Consumer;

vavr/src/main/java/io/vavr/collection/Array.java

@@ -18,21 +18,20 @@
  */
 package io.vavr.collection;
 
+import static io.vavr.collection.JavaConverters.ChangePolicy.IMMUTABLE;
+import static io.vavr.collection.JavaConverters.ChangePolicy.MUTABLE;
+import static java.util.Arrays.copyOf;
+import static java.util.Arrays.sort;
+
 import io.vavr.*;
 import io.vavr.collection.ArrayModule.Combinations;
 import io.vavr.collection.JavaConverters.ListView;
 import io.vavr.control.Option;
-
 import java.io.Serializable;
 import java.util.*;
 import java.util.function.*;
 import java.util.stream.Collector;
 
-import static io.vavr.collection.JavaConverters.ChangePolicy.IMMUTABLE;
-import static io.vavr.collection.JavaConverters.ChangePolicy.MUTABLE;
-import static java.util.Arrays.copyOf;
-import static java.util.Arrays.sort;
-
 /**
  * Array is a Traversable wrapper for {@code Object[]} containing elements of type {@code T}.
  *

vavr/src/main/java/io/vavr/collection/BitMappedTrie.java

@@ -18,16 +18,16 @@
  */
 package io.vavr.collection;
 
-import java.io.Serializable;
-import java.util.NoSuchElementException;
-import java.util.function.Function;
-import java.util.function.Predicate;
-
-import static java.util.function.Function.identity;
 import static io.vavr.collection.ArrayType.obj;
 import static io.vavr.collection.Collections.withSize;
 import static io.vavr.collection.NodeModifier.COPY_NODE;
 import static io.vavr.collection.NodeModifier.IDENTITY;
+import static java.util.function.Function.identity;
+
+import java.io.Serializable;
+import java.util.NoSuchElementException;
+import java.util.function.Function;
+import java.util.function.Predicate;
 
 /**
  * A `bit-mapped trie` is a very wide and shallow tree (for integer indices the depth will be `≤6`).

vavr/src/main/java/io/vavr/collection/BitSet.java

@@ -20,10 +20,9 @@
 
 import io.vavr.Function1;
 import io.vavr.PartialFunction;
-import io.vavr.Tuple3;
 import io.vavr.Tuple2;
+import io.vavr.Tuple3;
 import io.vavr.control.Option;
-
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Comparator;

vavr/src/main/java/io/vavr/collection/CharSeq.java

@@ -18,11 +18,13 @@
  */
 package io.vavr.collection;
 
+import static io.vavr.collection.JavaConverters.ChangePolicy.IMMUTABLE;
+import static io.vavr.collection.JavaConverters.ChangePolicy.MUTABLE;
+
 import io.vavr.*;
 import io.vavr.collection.CharSeqModule.Combinations;
 import io.vavr.collection.JavaConverters.ListView;
 import io.vavr.control.Option;
-
 import java.io.Serializable;
 import java.io.UnsupportedEncodingException;
 import java.nio.charset.Charset;
@@ -32,9 +34,6 @@
 import java.util.regex.PatternSyntaxException;
 import java.util.stream.Collector;
 
-import static io.vavr.collection.JavaConverters.ChangePolicy.IMMUTABLE;
-import static io.vavr.collection.JavaConverters.ChangePolicy.MUTABLE;
-
 /**
  * The CharSeq (read: character sequence) collection essentially is a rich String wrapper having all operations
  * we know from the functional Vavr collections.

vavr/src/main/java/io/vavr/collection/Collections.java

@@ -23,7 +23,6 @@
 import io.vavr.collection.JavaConverters.ChangePolicy;
 import io.vavr.collection.JavaConverters.ListView;
 import io.vavr.control.Option;
-
 import java.util.*;
 import java.util.function.*;
 import java.util.stream.Collector;

vavr/src/main/java/io/vavr/collection/Foldable.java

@@ -19,7 +19,6 @@
 package io.vavr.collection;
 
 import io.vavr.control.Option;
-
 import java.util.NoSuchElementException;
 import java.util.Objects;
 import java.util.function.BiFunction;

vavr/src/main/java/io/vavr/collection/HashArrayMappedTrie.java

@@ -18,19 +18,18 @@
  */
 package io.vavr.collection;
 
+import static io.vavr.collection.HashArrayMappedTrieModule.Action.PUT;
+import static io.vavr.collection.HashArrayMappedTrieModule.Action.REMOVE;
+import static java.lang.Integer.bitCount;
+import static java.util.Arrays.copyOf;
+
 import io.vavr.Tuple;
 import io.vavr.Tuple2;
 import io.vavr.collection.HashArrayMappedTrieModule.EmptyNode;
 import io.vavr.control.Option;
-
 import java.io.Serializable;
 import java.util.Objects;
 
-import static java.lang.Integer.bitCount;
-import static java.util.Arrays.copyOf;
-import static io.vavr.collection.HashArrayMappedTrieModule.Action.PUT;
-import static io.vavr.collection.HashArrayMappedTrieModule.Action.REMOVE;
-
 /**
  * An immutable <a href="https://en.wikipedia.org/wiki/Hash_array_mapped_trie">Hash array mapped trie (HAMT)</a>.
  *

vavr/src/main/java/io/vavr/collection/HashMap.java

@@ -21,7 +21,6 @@
 import io.vavr.Tuple;
 import io.vavr.Tuple2;
 import io.vavr.control.Option;
-
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Comparator;

vavr/src/main/java/io/vavr/collection/HashMultimap.java

@@ -19,7 +19,6 @@
 package io.vavr.collection;
 
 import io.vavr.Tuple2;
-
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Comparator;

vavr/src/main/java/io/vavr/collection/HashSet.java

@@ -20,7 +20,6 @@
 
 import io.vavr.*;
 import io.vavr.control.Option;
-
 import java.io.*;
 import java.util.ArrayList;
 import java.util.Comparator;

vavr/src/main/java/io/vavr/collection/IndexedSeq.java

@@ -19,10 +19,9 @@
 package io.vavr.collection;
 
 import io.vavr.PartialFunction;
-import io.vavr.Tuple3;
 import io.vavr.Tuple2;
+import io.vavr.Tuple3;
 import io.vavr.control.Option;
-
 import java.util.Comparator;
 import java.util.NoSuchElementException;
 import java.util.Objects;

vavr/src/main/java/io/vavr/collection/Iterator.java

@@ -18,25 +18,24 @@
  */
 package io.vavr.collection;
 
+import static io.vavr.collection.IteratorModule.BigDecimalHelper.areEqual;
+import static io.vavr.collection.IteratorModule.BigDecimalHelper.asDecimal;
+import static io.vavr.collection.IteratorModule.CachedIterator;
+import static io.vavr.collection.IteratorModule.EmptyIterator;
+import static java.lang.Double.NEGATIVE_INFINITY;
+import static java.lang.Double.POSITIVE_INFINITY;
+import static java.math.RoundingMode.HALF_UP;
+
 import io.vavr.*;
 import io.vavr.collection.IteratorModule.ConcatIterator;
 import io.vavr.collection.IteratorModule.DistinctIterator;
 import io.vavr.collection.IteratorModule.GroupedIterator;
 import io.vavr.control.Option;
-
 import java.math.BigDecimal;
 import java.util.*;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.*;
 
-import static java.lang.Double.NEGATIVE_INFINITY;
-import static java.lang.Double.POSITIVE_INFINITY;
-import static java.math.RoundingMode.HALF_UP;
-import static io.vavr.collection.IteratorModule.BigDecimalHelper.areEqual;
-import static io.vavr.collection.IteratorModule.BigDecimalHelper.asDecimal;
-import static io.vavr.collection.IteratorModule.CachedIterator;
-import static io.vavr.collection.IteratorModule.EmptyIterator;
-
 /**
  * {@code io.vavr.collection.Iterator} is a compositional replacement for {@code java.util.Iterator}
  * whose purpose is to iterate <em>once</em> over a sequence of elements.

vavr/src/main/java/io/vavr/collection/LinearSeq.java

@@ -20,9 +20,8 @@
 
 import io.vavr.PartialFunction;
 import io.vavr.Tuple;
-import io.vavr.control.Option;
 import io.vavr.Tuple2;
-
+import io.vavr.control.Option;
 import java.util.Comparator;
 import java.util.Objects;
 import java.util.function.*;

vavr/src/main/java/io/vavr/collection/LinkedHashMap.java

@@ -21,7 +21,6 @@
 import io.vavr.Tuple;
 import io.vavr.Tuple2;
 import io.vavr.control.Option;
-
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Comparator;

vavr/src/main/java/io/vavr/collection/LinkedHashMultimap.java

@@ -19,7 +19,6 @@
 package io.vavr.collection;
 
 import io.vavr.Tuple2;
-
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Comparator;