use List interface instead of ArrayList implementation in several places

src/main/java/eu/crushedpixel/replaymod/assets/CustomObjectRepository.java

@@ -1,18 +1,24 @@
 package eu.crushedpixel.replaymod.assets;
 
-import lombok.AllArgsConstructor;
-import lombok.Data;
+import lombok.Getter;
 
 import java.util.ArrayList;
+import java.util.List;
 
-@Data
-@AllArgsConstructor
 public class CustomObjectRepository {
 
     public CustomObjectRepository() {
         this.objects = new ArrayList<CustomImageObject>();
     }
+    public CustomObjectRepository(List<CustomImageObject> objects) {
+        setObjects(objects);
+    }
 
+    public void setObjects(List<CustomImageObject> objects) {
+        this.objects = new ArrayList<CustomImageObject>(objects);
+    }
+
+    @Getter
     private ArrayList<CustomImageObject> objects;
 
 }