Nonnull on events (#216)

* Nonnull on events

* Update GitHubBranchTrigger.java

Author: KostyaSha

github-pullrequest-plugin/src/main/java/com/github/kostyasha/github/integration/branch/GitHubBranchTrigger.java

@@ -30,7 +30,6 @@
 import javax.annotation.Nullable;
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.Date;
 import java.util.LinkedHashSet;
 import java.util.List;
@@ -45,6 +44,7 @@
 import static com.google.common.base.Charsets.UTF_8;
 import static com.google.common.base.Predicates.not;
 import static java.text.DateFormat.getDateTimeInstance;
+import static java.util.Collections.emptyList;
 import static org.jenkinsci.plugins.github.pullrequest.GitHubPRTriggerMode.LIGHT_HOOKS;
 import static org.jenkinsci.plugins.github.pullrequest.utils.ObjectsUtil.isNull;
 import static org.jenkinsci.plugins.github.pullrequest.utils.ObjectsUtil.nonNull;
@@ -99,9 +99,9 @@ public boolean isPreStatus() {
         return preStatus;
     }
 
-    @CheckForNull
+    @Nonnull
     public List<GitHubBranchEvent> getEvents() {
-        return events;
+        return nonNull(events) ? events : emptyList();
     }
 
     @CheckForNull
@@ -241,7 +241,7 @@ private List<GitHubBranchCause> readyToBuildCauses(GitHubBranchRepository localR
             return causes;
         } catch (IOException e) {
             listener.error("Can't get build causes: '{}'", e);
-            return Collections.emptyList();
+            return emptyList();
         }
     }
 

github-pullrequest-plugin/src/main/java/org/jenkinsci/plugins/github/pullrequest/GitHubPRTrigger.java

@@ -138,8 +138,9 @@ public boolean isPreStatus() {
         return preStatus;
     }
 
+    @Nonnull
     public List<GitHubPREvent> getEvents() {
-        return events;
+        return nonNull(events) ? events : emptyList();
     }
 
     public GitHubPRUserRestriction getUserRestriction() {