Replace addAll with parameterized constructor call.

src/main/java/org/torproject/onionoo/docs/UptimeHistory.java

@@ -88,8 +88,7 @@ public class UptimeHistory implements Comparable<UptimeHistory> {
     }
     SortedSet<String> flags = null;
     if (parts[0].equals("R")) {
-      flags = new TreeSet<>();
-      flags.addAll(Arrays.asList(parts).subList(3, parts.length));
+      flags = new TreeSet<>(Arrays.asList(parts).subList(3, parts.length));
     }
     return new UptimeHistory(relay, startMillis, uptimeHours, flags);
   }

src/test/java/org/torproject/onionoo/updater/DummyDescriptorSource.java

@@ -52,8 +52,8 @@ public class DummyDescriptorSource extends DescriptorSource {
 
   @Override
   public void readDescriptors() {
-    Set<DescriptorType> descriptorTypes = new HashSet<>();
-    descriptorTypes.addAll(this.descriptorListeners.keySet());
+    Set<DescriptorType> descriptorTypes = new HashSet<>(
+        this.descriptorListeners.keySet());
     for (DescriptorType descriptorType : descriptorTypes) {
       boolean relay;
       switch (descriptorType) {