Tries to fix a stack trace when Dynmap fails to disable itself

src/main/java/net/knarcraft/stargate/config/DynmapManager.java

@@ -27,8 +27,9 @@ public final class DynmapManager {
      * Initializes the dynmap manager
      *
      * @param dynmapAPI <p>A reference</p>
+     * @throws NullPointerException <p>If dynmap has an invalid state</p>
      */
-    public static void initialize(DynmapAPI dynmapAPI) {
+    public static void initialize(DynmapAPI dynmapAPI) throws NullPointerException {
         if (dynmapAPI == null || dynmapAPI.getMarkerAPI() == null) {
             markerSet = null;
             portalIcon = null;

src/main/java/net/knarcraft/stargate/config/StargateConfig.java

@@ -108,8 +108,13 @@ public final class StargateConfig {
         setupVaultEconomy();
         DynmapAPI dynmapAPI = (DynmapAPI) Bukkit.getPluginManager().getPlugin("dynmap");
         if (dynmapAPI != null) {
-            DynmapManager.initialize(dynmapAPI);
-            DynmapManager.addAllPortalMarkers();
+            try {
+                DynmapManager.initialize(dynmapAPI);
+                DynmapManager.addAllPortalMarkers();
+            } catch (NullPointerException exception) {
+                logger.warning("Dynmap started in an invalid state. Check your log/console for dynmap-related " +
+                        "problems. Dynmap integration cannot be initialized.");
+            }
         }
 
         this.isLoaded = true;