diff --git a/src/main/java/ch/njol/skript/classes/data/JavaClasses.java b/src/main/java/ch/njol/skript/classes/data/JavaClasses.java
index 6ad2c4d9db7..b2af31d3bc5 100644
--- a/src/main/java/ch/njol/skript/classes/data/JavaClasses.java
+++ b/src/main/java/ch/njol/skript/classes/data/JavaClasses.java
@@ -843,8 +843,8 @@ public Fields serialize(UUID uuid) {
 		}
 
 		@Override
-		public void deserialize(UUID o, Fields f) throws NotSerializableException {
-			throw new NotSerializableException();
+		public void deserialize(UUID o, Fields f) {
+			assert false;
 		}
 
 		@Override