Merge pull request #8685 from protocolbuffers/addDokka

Adding dokka to main pom
diff --git a/java/pom.xml b/java/pom.xml
index 5cfb67f..3a774ec 100644
--- a/java/pom.xml
+++ b/java/pom.xml
@@ -228,6 +228,19 @@
               <autoReleaseAfterClose>false</autoReleaseAfterClose>
             </configuration>
           </plugin>
+          <plugin>
+            <groupId>org.jetbrains.dokka</groupId>
+            <artifactId>dokka-maven-plugin</artifactId>
+            <version>1.4.32</version>
+            <executions>
+              <execution>
+                <phase>prepare-package</phase>
+                <goals>
+                  <goal>javadocJar</goal>
+                </goals>
+              </execution>
+            </executions>
+          </plugin>
         </plugins>
       </build>
     </profile>