Fix checkstyle errors when building archetype-generated apps

Checkstyle validation is now enabled by default in onos-dependencies
(archetypes' parent pom). We also add a reference to the archetypes' pom
to disable checkstyle, if needed.

Change-Id: I9b6e6cecf2d704f52ec1f118eae2aafd03cf0b9a
diff --git a/tools/package/archetypes/api/src/main/resources/archetype-resources/pom.xml b/tools/package/archetypes/api/src/main/resources/archetype-resources/pom.xml
index acded36..ba79393 100644
--- a/tools/package/archetypes/api/src/main/resources/archetype-resources/pom.xml
+++ b/tools/package/archetypes/api/src/main/resources/archetype-resources/pom.xml
@@ -19,7 +19,9 @@
   ~ See the License for the specific language governing permissions and
   ~ limitations under the License.
   -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
 
     <parent>
@@ -45,4 +47,18 @@
         </dependency>
     </dependencies>
 
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-checkstyle-plugin</artifactId>
+                <!-- Uncomment to disable checkstyle validation
+                <configuration>
+                    <skip>true</skip>
+                </configuration>
+                -->
+            </plugin>
+        </plugins>
+    </build>
+
 </project>
diff --git a/tools/package/archetypes/api/src/main/resources/archetype-resources/src/main/java/package-info.java b/tools/package/archetypes/api/src/main/resources/archetype-resources/src/main/java/package-info.java
new file mode 100644
index 0000000..3d2d640
--- /dev/null
+++ b/tools/package/archetypes/api/src/main/resources/archetype-resources/src/main/java/package-info.java
@@ -0,0 +1,23 @@
+#set( $symbol_pound = '#' )
+#set( $symbol_dollar = '$' )
+#set( $symbol_escape = '\' )
+/*
+ * Copyright ${year}-present Open Networking Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * The ${artifactId} application.
+ */
+package ${package};