Fixs some misspellings

Change-Id: I03d23d8acca8789b430f74fdac80d287f0fa59df
diff --git a/core/api/src/main/java/org/onosproject/net/statistic/StatisticService.java b/core/api/src/main/java/org/onosproject/net/statistic/StatisticService.java
index d8162ec..1bf30ca 100644
--- a/core/api/src/main/java/org/onosproject/net/statistic/StatisticService.java
+++ b/core/api/src/main/java/org/onosproject/net/statistic/StatisticService.java
@@ -27,7 +27,7 @@
 /**
  * Service for obtaining statistic information about link in the system.
  * Statistics are obtained from the FlowRuleService in order to minimize the
- * amount of hammering occuring at the dataplane.
+ * amount of hammering occurring at the dataplane.
  */
 public interface StatisticService {
 
diff --git a/core/api/src/test/java/org/onosproject/store/service/TestDocumentTreeNode.java b/core/api/src/test/java/org/onosproject/store/service/TestDocumentTreeNode.java
index 508fad2..665355f 100644
--- a/core/api/src/test/java/org/onosproject/store/service/TestDocumentTreeNode.java
+++ b/core/api/src/test/java/org/onosproject/store/service/TestDocumentTreeNode.java
@@ -76,7 +76,7 @@
      * @param newValue new value to set
      * @param newVersion new version to set
      * @return previous value; can be {@code null} if no child currently exists with that relative path name.
-     * a non null return value indicates child already exists and no modification occured.
+     * a non null return value indicates child already exists and no modification occurred.
      */
     public Versioned<V> addChild(String name, V newValue, long newVersion) {
         TestDocumentTreeNode<V> child = (TestDocumentTreeNode<V>) children.get(name);