diff --git a/src/main/java/xyz/zhouxy/plusone/validator/MapValidator.java b/src/main/java/xyz/zhouxy/plusone/validator/MapValidator.java
index cfc4437..855010d 100644
--- a/src/main/java/xyz/zhouxy/plusone/validator/MapValidator.java
+++ b/src/main/java/xyz/zhouxy/plusone/validator/MapValidator.java
@@ -35,6 +35,7 @@ public class MapValidator {
         this.rules.add(rule);
     }
 
+    @SuppressWarnings("unchecked")
     protected final <R> ObjectValidator<Map<String, Object>, R> ruleFor(String key) {
         ObjectValidator<Map<String, Object>, R> validValueHolder = new ObjectValidator<>(map -> (R) map.get(key));
         propertyValidators.add(validValueHolder);
@@ -65,6 +66,7 @@ public class MapValidator {
         return validValueHolder;
     }
 
+    @SuppressWarnings("unchecked")
     protected final <E> CollectionValidator<Map<String, Object>, E> ruleForCollection(String key) {
         CollectionValidator<Map<String, Object>, E> validValueHolder = new CollectionValidator<>(m -> (Collection<E>) m.get(key));
         propertyValidators.add(validValueHolder);