Use diamond operator

Author: junichi11

src/main/java/com/junichi11/netbeans/modules/github/issues/GitHubCache.java

@@ -82,7 +82,7 @@ public final class GitHubCache {
     // @GuardedBy("this")
     private List<User> collaborators;
     // @GuardedBy("this")
-    private final Map<String, List<Milestone>> milestoneMap = Collections.synchronizedMap(new HashMap<String, List<Milestone>>());
+    private final Map<String, List<Milestone>> milestoneMap = Collections.synchronizedMap(new HashMap<>());
     // @GuardedBy("this")
     private List<Label> labels;
     // @GuardedBy("this")

src/main/java/com/junichi11/netbeans/modules/github/issues/issue/ui/CommentsPanel.java

@@ -61,7 +61,7 @@ public class CommentsPanel extends javax.swing.JPanel implements PropertyChangeL
 
     private static final long serialVersionUID = 3131157719093603387L;
 
-    private final List<CommentPanel> commentPanels = Collections.synchronizedList(new ArrayList<CommentPanel>());
+    private final List<CommentPanel> commentPanels = Collections.synchronizedList(new ArrayList<>());
     private CommentPanel quoteCommentPanel;
     private CommentPanel deletedCommentPanel;
     private CommentPanel editedCommentPanel;

src/main/java/com/junichi11/netbeans/modules/github/issues/repository/GitHubRepository.java

@@ -110,9 +110,9 @@ public class GitHubRepository {
 
     // caches
     // @GaurdedBy("this")
-    private final Map<String, GitHubIssue> issueCache = Collections.synchronizedMap(new HashMap<String, GitHubIssue>());
+    private final Map<String, GitHubIssue> issueCache = Collections.synchronizedMap(new HashMap<>());
     // @GaurdedBy("this")
-    private final Map<String, PullRequest> pullRequestCache = Collections.synchronizedMap(new HashMap<String, PullRequest>());
+    private final Map<String, PullRequest> pullRequestCache = Collections.synchronizedMap(new HashMap<>());
 
     private Boolean isCollaborator = null;