Generate javadocs in Maven build

Change-Id: I5b3c5de186d101d3fd03bbee6df4e55ebfa889c4
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

pom.xml

diff --git a/pom.xml b/pom.xml
index 95a65d1..d5b3bd8 100644
--- a/pom.xml
+++ b/pom.xml
@@ -327,6 +327,26 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-javadoc-plugin</artifactId>
+        <version>2.9.1</version>
+        <configuration>
+          <encoding>UTF-8</encoding>
+          <quiet>true</quiet>
+          <links>
+            <link>http://java.sun.com/j2se/1.7.0/docs/api</link>
+          </links>
+        </configuration>
+        <executions>
+          <execution>
+            <id>attach-javadocs</id>
+            <goals>
+              <goal>jar</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
     </plugins>
     <extensions>
       <extension>