Revert "Drop caching resources with no benefit"

This reverts commit 9a27d56.

server/src/main/java/com/soulfiremc/server/data/GsonDataHelper.java

@@ -27,6 +27,7 @@
 import net.kyori.adventure.key.Key;
 
 import java.io.IOException;
+import java.util.HashMap;
 import java.util.Map;
 import java.util.function.Function;
 
@@ -45,6 +46,7 @@ public Key read(JsonReader in) throws IOException {
         return Key.key(key);
       }
     };
+  private static final Map<String, JsonArray> LOADED_DATA = new HashMap<>();
   private static final Function<Map<Class<?>, Object>, Gson> GSON_FACTORY = (typeAdapters) -> {
     var builder = new GsonBuilder()
       .registerTypeAdapter(Key.class, RESOURCE_KEY_ADAPTER)
@@ -64,14 +66,19 @@ public static <T> T fromJson(String dataFile, String dataKey, Class<T> clazz) {
   public static <T> T fromJson(String dataFile, String dataKey, Class<T> clazz,
                                Map<Class<?>, Object> typeAdapters) {
     var gson = createGson(typeAdapters);
-    var array = new JsonArray();
-    try {
-      array =
-        gson.fromJson(SFHelpers.getResourceAsString(dataFile), JsonArray.class);
-    } catch (Exception e) {
-      throw new RuntimeException("Failed to load data file " + dataFile, e);
-    }
-
+    var array =
+      LOADED_DATA.computeIfAbsent(
+        dataFile,
+        file -> {
+          var data = new JsonArray();
+          try {
+            data =
+              gson.fromJson(SFHelpers.getResourceAsString(file), JsonArray.class);
+          } catch (Exception e) {
+            throw new RuntimeException("Failed to load data file " + file, e);
+          }
+          return data;
+        });
     for (var element : array) {
       if (element.getAsJsonObject().get("key").getAsString().equals(dataKey)) {
         return gson.fromJson(element, clazz);