Add main.class to hello-world example

Author: ansell

maven/hello-world/pom.xml

@@ -11,8 +11,8 @@
 
     <properties>
         <kotlin.version>1.0.1-2</kotlin.version>
-        <junit.version>4.10</junit.version>
-
+        <junit.version>4.12</junit.version>
+	<main.class>hello.HelloKt</main.class>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
 
@@ -65,6 +65,19 @@
                     </execution>
                 </executions>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <version>2.6</version>
+                <configuration>
+                    <archive>
+                        <manifest>
+                            <addClasspath>true</addClasspath>
+                            <mainClass>${main.class}</mainClass>
+                        </manifest>
+                    </archive>
+                </configuration>
+            </plugin>
             <plugin>
                 <groupId>org.codehaus.mojo</groupId>
                 <artifactId>exec-maven-plugin</artifactId>
@@ -78,7 +91,7 @@
                     </execution>
                 </executions>
                 <configuration>
-                    <mainClass>hello.HelloKt</mainClass>
+                    <mainClass>${main.class}</mainClass>
                 </configuration>
             </plugin>
         </plugins>