add javadoc for release (#851)

Author: slievrly

pom.xml

@@ -85,7 +85,7 @@
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <!-- Maven properties -->
         <maven.test.skip>false</maven.test.skip>
-        <maven.javadoc.skip>true</maven.javadoc.skip>
+        <!--<maven.javadoc.skip>true</maven.javadoc.skip>-->
         <!-- Compiler settings properties -->
         <maven.compiler.source>1.8</maven.compiler.source>
         <maven.compiler.target>1.8</maven.compiler.target>
@@ -403,6 +403,7 @@
                         <version>${maven-javadoc-plugin.version}</version>
                         <configuration>
                             <charset>UTF-8</charset>
+                            <failOnError>false</failOnError>
                         </configuration>
                         <executions>
                             <execution>