diff --git a/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/MapValidator.java b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/MapValidator.java
index dabe9a4..859ea8e 100644
--- a/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/MapValidator.java
+++ b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/MapValidator.java
@@ -16,7 +16,7 @@
 
 package xyz.zhouxy.plusone.validator;
 
-import java.util.AbstractMap.SimpleEntry;
+import java.util.AbstractMap.SimpleImmutableEntry;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Map;
@@ -205,7 +205,8 @@ public abstract class MapValidator<K, V> extends BaseValidator<Map<K, V>> {
     protected final <V1 extends V, V2 extends V>
     PairPropertyValidator<Map<K, V>, V1, V2> ruleForPair(K k1, K k2) {
         @SuppressWarnings("unchecked")
-        Function<Map<K, V>, Entry<V1, V2>> getter = m -> new SimpleEntry<V1, V2>((V1) m.get(k1), (V2) m.get(k2));
+        Function<Map<K, V>, Entry<V1, V2>> getter = m ->
+                new SimpleImmutableEntry<>((V1) m.get(k1), (V2) m.get(k2));
         return ruleForPair(getter);
     }
 
diff --git a/plusone-validator/src/test/java/xyz/zhouxy/plusone/example/validator/PairPropertyValidatorTests.java b/plusone-validator/src/test/java/xyz/zhouxy/plusone/example/validator/PairPropertyValidatorTests.java
index 7b7ed03..29c61d1 100644
--- a/plusone-validator/src/test/java/xyz/zhouxy/plusone/example/validator/PairPropertyValidatorTests.java
+++ b/plusone-validator/src/test/java/xyz/zhouxy/plusone/example/validator/PairPropertyValidatorTests.java
@@ -21,7 +21,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.Objects;
-import java.util.AbstractMap.SimpleEntry;
+import java.util.AbstractMap.SimpleImmutableEntry;
 
 import org.junit.jupiter.api.Test;
 
@@ -43,7 +43,7 @@ public class PairPropertyValidatorTests {
     void must_validInput() {
         IValidator<ExampleCommand> validator = new BaseValidator<ExampleCommand>() {
             {
-                ruleForPair((ExampleCommand command) -> new SimpleEntry<String,Integer>(command.getStringProperty(), command.getIntProperty()))
+                ruleForPair((ExampleCommand command) -> new SimpleImmutableEntry<String,Integer>(command.getStringProperty(), command.getIntProperty()))
                         .must((str, intValue) -> Objects.equals(str, intValue.toString()))
                         .must((str, intValue) -> Objects.equals(str, intValue.toString()), MESSAGE)
                         .must((str, intValue) -> Objects.equals(str, intValue.toString()), () -> ExampleException.withMessage(MESSAGE))
@@ -60,7 +60,7 @@ public class PairPropertyValidatorTests {
     void must_default_invalidInput() {
         IValidator<ExampleCommand> validator = new BaseValidator<ExampleCommand>() {
             {
-                ruleForPair((ExampleCommand command) -> new SimpleEntry<String,Integer>(command.getStringProperty(), command.getIntProperty()))
+                ruleForPair((ExampleCommand command) -> new SimpleImmutableEntry<String,Integer>(command.getStringProperty(), command.getIntProperty()))
                         .must((str, intValue) -> Objects.equals(str, intValue.toString()));
             }
         };
@@ -75,7 +75,7 @@ public class PairPropertyValidatorTests {
     void must_message_invalidInput() {
         IValidator<ExampleCommand> validator = new BaseValidator<ExampleCommand>() {
             {
-                ruleForPair((ExampleCommand command) -> new SimpleEntry<String,Integer>(command.getStringProperty(), command.getIntProperty()))
+                ruleForPair((ExampleCommand command) -> new SimpleImmutableEntry<String,Integer>(command.getStringProperty(), command.getIntProperty()))
                         .must((str, intValue) -> Objects.equals(str, intValue.toString()), MESSAGE);
             }
         };
@@ -89,7 +89,7 @@ public class PairPropertyValidatorTests {
     void must_exceptionSupplier_invalidInput() {
         IValidator<ExampleCommand> validator = new BaseValidator<ExampleCommand>() {
             {
-                ruleForPair((ExampleCommand command) -> new SimpleEntry<String,Integer>(command.getStringProperty(), command.getIntProperty()))
+                ruleForPair((ExampleCommand command) -> new SimpleImmutableEntry<String,Integer>(command.getStringProperty(), command.getIntProperty()))
                         .must((str, intValue) -> Objects.equals(str, intValue.toString()), () -> ExampleException.withMessage(MESSAGE));
             }
         };
@@ -104,7 +104,7 @@ public class PairPropertyValidatorTests {
     void must_exceptionFunction_invalidInput() {
         IValidator<ExampleCommand> validator = new BaseValidator<ExampleCommand>() {
             {
-                ruleForPair((ExampleCommand command) -> new SimpleEntry<String,Integer>(command.getStringProperty(), command.getIntProperty()))
+                ruleForPair((ExampleCommand command) -> new SimpleImmutableEntry<String,Integer>(command.getStringProperty(), command.getIntProperty()))
                         .must((str, intValue) -> Objects.equals(str, intValue.toString()),
                                 (str, intValue) -> ExampleException.withMessage("Validation failed: ('%s', %d).", str, intValue));
             }