Fail Maven build on warnings (#2335)

* Fail Maven build on warnings

* Fix configuration parameter name

For the Javadoc plugin it is "warnings" (plural) instead of "warning"

gson/pom.xml

@@ -55,12 +55,6 @@
  <version>31.1-jre</version>
  <scope>test</scope>
  </dependency>
- <dependency>
- <groupId>com.google.errorprone</groupId>
- <artifactId>error_prone_annotations</artifactId>
- <version>2.18.0</version>
- <optional>true</optional>
- </dependency>
  </dependencies>
 
  <build>

pom.xml

@@ -85,6 +85,18 @@
  </dependencies>
  </dependencyManagement>
 
+ <dependencies>
+ <!-- Error Prone Annotations is only directly used by gson module, but since this is an optional
+ dependency and other modules depend on gson module they also need the dependency to avoid
+ compiler warnings, see comments on https://bugs.openjdk.org/browse/JDK-6331821 -->
+ <dependency>
+ <groupId>com.google.errorprone</groupId>
+ <artifactId>error_prone_annotations</artifactId>
+ <version>2.18.0</version>
+ <optional>true</optional>
+ </dependency>
+ </dependencies>
+
  <build>
  <plugins>
  <plugin>
@@ -120,6 +132,7 @@
  <configuration>
  <showWarnings>true</showWarnings>
  <showDeprecation>true</showDeprecation>
+ <failOnWarning>true</failOnWarning>
  <fork>true</fork>
  <compilerArgs>
  <!-- Args related to Error Prone, see: https://errorprone.info/docs/installation#maven -->
@@ -173,6 +186,7 @@
  <detectOfflineLinks>false</detectOfflineLinks>
  <!-- Only show warnings and errors -->
  <quiet>true</quiet>
+ <failOnWarnings>true</failOnWarnings>
  </configuration>
  </plugin>
  <plugin>