Build: Add Error Prone plugin (#155)

* Add Error-Prone annotation processor

* Enable ErrorProne

* Suppress warnings about StreamToString

* Fix ReturnValueIgnored

* Suppress warnings about EqualsHashCode

* Add org.immutables:value as annotation processor

* Fix ReturnValueIgnored

* Add JMH generator as annotation processor

* Suppress warnings about ReturnValueIgnored

* Fix ReturnValueIgnored

* Suppress warnings about FormatString and ArrayToString

* Fix more warnings

* Fix CollectionIncompatibleType

* Fix FormatString

Author: mincong-h

concurrency/src/main/java/io/mincong/concurrency/completablefuture/stackoverflow/So61957439.java

@@ -32,6 +32,7 @@
  * 08:20:10.165436 - [Result{name='C3'}, Result{name='C1'}, Result{name='C2'}]
  * </pre>
  */
+@SuppressWarnings("StreamToString")
 public class So61957439 {
 
   public static void main(String[] args) throws Exception {

date/src/test/java/io/mincongh/date/so42364818/DateTest.java

@@ -20,7 +20,6 @@ void testDate() throws Exception {
     assertEquals(45, d.getMinute());
     assertEquals(30, d.getSecond());
 
-    d.format(DateTimeFormatter.ISO_LOCAL_DATE_TIME);
     assertEquals("2009-06-15T13:45:30", d.format(DateTimeFormatter.ISO_LOCAL_DATE_TIME));
   }
 }

hashcode/src/main/java/io/mincongh/hashcode/bad/AthleteOnlyOverrideEquals.java

@@ -6,6 +6,7 @@
  *
  * @author Mincong Huang
  */
+@SuppressWarnings("EqualsHashCode") // hashCode() unimplemented for demo purpose
 public class AthleteOnlyOverrideEquals {
 
   private String email;

hashcode/src/main/java/io/mincongh/hashcode/bad/PhoneNumberNoHash.java

@@ -1,6 +1,7 @@
 package io.mincongh.hashcode.bad;
 
 /** @author Mincong Huang */
+@SuppressWarnings("EqualsHashCode") // hashCode() unimplemented for demo purpose
 public class PhoneNumberNoHash {
 
   private final short areaCode;

immutables/pom.xml

@@ -14,15 +14,10 @@
   <artifactId>java-examples-immutables</artifactId>
   <name>Java Examples - Immutables</name>
 
-  <properties>
-    <immutables.version>2.8.8</immutables.version>
-  </properties>
-
   <dependencies>
     <dependency>
       <groupId>org.immutables</groupId>
       <artifactId>value</artifactId>
-      <version>${immutables.version}</version>
       <scope>provided</scope>
     </dependency>
     <!--

java8/src/test/java/io/mincongh/java8/so2607289/ConvertArrayToListTest.java

@@ -4,7 +4,7 @@
 import static org.junit.jupiter.api.Assertions.fail;
 
 import java.util.*;
-import java.util.function.Predicate;
+import java.util.function.Consumer;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import org.junit.jupiter.api.Test;
@@ -71,13 +71,13 @@ private void assertListValues(List<Integer> list) {
     assertEquals(3, list.get(2).intValue());
   }
 
-  private <T> void assertOperationSupported(List<T> list, Predicate<List<T>> predicate) {
-    predicate.test(list);
+  private <T> void assertOperationSupported(List<T> list, Consumer<List<T>> action) {
+    action.accept(list);
   }
 
-  private <T> void assertOperationUnsupported(List<T> list, Predicate<List<T>> predicate) {
+  private <T> void assertOperationUnsupported(List<T> list, Consumer<List<T>> action) {
     try {
-      predicate.test(list);
+      action.accept(list);
       fail();
     } catch (UnsupportedOperationException e) {
       // Ok

jmh/pom.xml

@@ -16,7 +16,6 @@
 
   <properties>
     <commons.codec.version>1.15</commons.codec.version>
-    <jmh.version>1.26</jmh.version>
   </properties>
 
   <dependencies>
@@ -32,12 +31,6 @@
       <version>${jmh.version}</version>
       <scope>test</scope>
     </dependency>
-    <dependency>
-      <groupId>org.openjdk.jmh</groupId>
-      <artifactId>jmh-generator-annprocess</artifactId>
-      <version>${jmh.version}</version>
-      <scope>test</scope>
-    </dependency>
     <dependency>
       <groupId>org.junit.jupiter</groupId>
       <artifactId>junit-jupiter-api</artifactId>

oca/src/test/java/io/mincong/ocajp/chapter3/ReviewQuestionTest.java

@@ -56,6 +56,7 @@ public void testLegalArrayDeclaration() {
 
   /** Question 31. */
   @Test
+  @SuppressWarnings("ReturnValueIgnored")
   public void testLocalDateImmutability() {
     LocalDate date = LocalDate.of(2018, Month.APRIL, 30);
     date.plusDays(2);

ocp/src/test/java/io/mincong/ocpjp/autoboxing/WrapperClassTest.java

@@ -62,6 +62,7 @@ public void comparingObjects() throws Exception {
      * Cannot use a `Float` object to retrieve the value that was
      * added to a `HashMap` using a `Double` instance.
      */
+    @SuppressWarnings("CollectionIncompatibleType")
     String value2 = map.get(new Float(2.0));
     assertThat(value2).isNull();
   }

ocp/src/test/java/io/mincong/ocpjp/collection/HashSetTest.java

@@ -146,6 +146,7 @@ public int hashCode() {
   }
 
   /** Only {@link #equals(Object)} is overridden. */
+  @SuppressWarnings("EqualsHashCode")
   private static class Person_E extends Person {
 
     Person_E(String name) {