Added javadoc comment to onos.impl package.
diff --git a/core/net/src/main/java/org/onlab/onos/impl/package-info.java b/core/net/src/main/java/org/onlab/onos/impl/package-info.java
index bbe539f..2bf17b3 100644
--- a/core/net/src/main/java/org/onlab/onos/impl/package-info.java
+++ b/core/net/src/main/java/org/onlab/onos/impl/package-info.java
@@ -1,4 +1,4 @@
 /**
- *
+ * Miscellaneous core system implementations.
  */
 package org.onlab.onos.impl;
\ No newline at end of file