Feature/less ticks

src/main/java/com/minecolonies/coremod/colony/Colony.java

@@ -619,10 +619,16 @@ public void onWorldUnload(@NotNull final World w)
      */
     public void onServerTick(@NotNull final TickEvent.ServerTickEvent event)
     {
+        packageManager.updateSubscribers();
+
+        if (packageManager.getSubscribers().isEmpty())
+        {
+            return;
+        }
+
         buildingManager.tick(event);
 
         getRequestManager().update();
-        packageManager.updateSubscribers();
 
         final List<EntityPlayer> visitors = new ArrayList<>(visitingPlayers);
 
@@ -740,15 +746,16 @@ public void onWorldTick(@NotNull final TickEvent.WorldTickEvent event)
             return;
         }
 
-        //  Cleanup Buildings whose Blocks have gone AWOL
-        buildingManager.cleanUpBuildings(event);
-
         // Clean up or spawn citizens.
-        if (!packageManager.getSubscribers().isEmpty())
+        if (packageManager.getSubscribers().isEmpty())
         {
-            citizenManager.onWorldTick(event);
+            return;
         }
 
+        //  Cleanup Buildings whose Blocks have gone AWOL
+        buildingManager.cleanUpBuildings(event);
+        citizenManager.onWorldTick(event);
+
         if (shallUpdate(world, TICKS_SECOND)
                 && event.world.getDifficulty() != EnumDifficulty.PEACEFUL
                 && Configurations.gameplay.doBarbariansSpawn

src/main/java/com/minecolonies/coremod/entity/ai/citizen/builder/EntityAIStructureBuilder.java

@@ -149,6 +149,11 @@ public IAIState pickUpMaterial()
         needsCurrently = neededItemsList.get(pickUpCount);
         pickUpCount++;
 
+        if (currentStructure == null)
+        {
+            return IDLE;
+        }
+
         if (currentStructure.getStage() != Structure.Stage.DECORATE)
         {
             needsCurrently = needsCurrently.and(stack -> !ItemStackUtils.isDecoration(stack));