Changed cache value's key to be final.

src/main/java/ca/recrown/islandsurvivalcraft/utilities/caching/CacheValue.java

@@ -4,7 +4,7 @@ class CacheValue<KeyType, ValueType> {
     /**
      * The key that represents this cache value in the caches hashmap.
      */
-    public volatile KeyType key;
+    public final KeyType key;
 
     /**
      * The actual value that this cache value stores.