Add log message to display the JVM version

Change-Id: I94bde3d825df80761a250364b5c7fc2e565a142f
diff --git a/core/net/src/main/java/org/onosproject/core/impl/CoreManager.java b/core/net/src/main/java/org/onosproject/core/impl/CoreManager.java
index f707c26..e82efd7 100644
--- a/core/net/src/main/java/org/onosproject/core/impl/CoreManager.java
+++ b/core/net/src/main/java/org/onosproject/core/impl/CoreManager.java
@@ -104,6 +104,9 @@
     protected void activate() {
         registerApplication(CORE_APP_NAME);
         cfgService.registerProperties(getClass());
+        log.info("ONOS starting up on Java version {}, JVM version {}",
+            System.getProperty("java.version"),
+            System.getProperty("java.vm.version"));
     }
 
     @Deactivate