diff --git a/src/main/java/it/cavallium/data/generator/nativedata/NullableInt52.java b/src/main/java/it/cavallium/data/generator/nativedata/NullableInt52.java
index 3e6839a..a85a61f 100644
--- a/src/main/java/it/cavallium/data/generator/nativedata/NullableInt52.java
+++ b/src/main/java/it/cavallium/data/generator/nativedata/NullableInt52.java
@@ -98,7 +98,7 @@ public class NullableInt52 implements Serializable, IGenericNullable {
 
 	@Override
 	public int hashCode() {
-		return Objects.hash(value);
+		return value == null ? 0 : value.hashCode();
 	}
 
 	@Override
diff --git a/src/main/java/it/cavallium/data/generator/nativedata/NullableString.java b/src/main/java/it/cavallium/data/generator/nativedata/NullableString.java
index afd7d04..fb5e454 100644
--- a/src/main/java/it/cavallium/data/generator/nativedata/NullableString.java
+++ b/src/main/java/it/cavallium/data/generator/nativedata/NullableString.java
@@ -114,7 +114,7 @@ public class NullableString implements Serializable, IGenericNullable {
 
 	@Override
 	public int hashCode() {
-		return Objects.hash(value);
+		return value == null ? 0 : value.hashCode();
 	}
 
 	@Override
diff --git a/src/main/java/it/cavallium/data/generator/nativedata/Nullableboolean.java b/src/main/java/it/cavallium/data/generator/nativedata/Nullableboolean.java
index da7fc09..2db6631 100644
--- a/src/main/java/it/cavallium/data/generator/nativedata/Nullableboolean.java
+++ b/src/main/java/it/cavallium/data/generator/nativedata/Nullableboolean.java
@@ -96,7 +96,7 @@ public class Nullableboolean implements Serializable, IGenericNullable {
 
 	@Override
 	public int hashCode() {
-		return Objects.hash(value);
+		return value == null ? 0 : value.hashCode();
 	}
 
 	@Override
diff --git a/src/main/java/it/cavallium/data/generator/nativedata/Nullablebyte.java b/src/main/java/it/cavallium/data/generator/nativedata/Nullablebyte.java
index 0cc998a..fbbdf6b 100644
--- a/src/main/java/it/cavallium/data/generator/nativedata/Nullablebyte.java
+++ b/src/main/java/it/cavallium/data/generator/nativedata/Nullablebyte.java
@@ -96,7 +96,7 @@ public class Nullablebyte implements Serializable, IGenericNullable {
 
 	@Override
 	public int hashCode() {
-		return Objects.hash(value);
+		return value == null ? 0 : value.hashCode();
 	}
 
 	@Override
diff --git a/src/main/java/it/cavallium/data/generator/nativedata/Nullablechar.java b/src/main/java/it/cavallium/data/generator/nativedata/Nullablechar.java
index 00806ab..bfcd11d 100644
--- a/src/main/java/it/cavallium/data/generator/nativedata/Nullablechar.java
+++ b/src/main/java/it/cavallium/data/generator/nativedata/Nullablechar.java
@@ -96,7 +96,7 @@ public class Nullablechar implements Serializable, IGenericNullable {
 
 	@Override
 	public int hashCode() {
-		return Objects.hash(value);
+		return value == null ? 0 : value.hashCode();
 	}
 
 	@Override
diff --git a/src/main/java/it/cavallium/data/generator/nativedata/Nullabledouble.java b/src/main/java/it/cavallium/data/generator/nativedata/Nullabledouble.java
index 2b20e0e..0b330ec 100644
--- a/src/main/java/it/cavallium/data/generator/nativedata/Nullabledouble.java
+++ b/src/main/java/it/cavallium/data/generator/nativedata/Nullabledouble.java
@@ -96,7 +96,7 @@ public class Nullabledouble implements Serializable, IGenericNullable {
 
 	@Override
 	public int hashCode() {
-		return Objects.hash(value);
+		return value == null ? 0 : value.hashCode();
 	}
 
 	@Override
diff --git a/src/main/java/it/cavallium/data/generator/nativedata/Nullablefloat.java b/src/main/java/it/cavallium/data/generator/nativedata/Nullablefloat.java
index c882061..1eea811 100644
--- a/src/main/java/it/cavallium/data/generator/nativedata/Nullablefloat.java
+++ b/src/main/java/it/cavallium/data/generator/nativedata/Nullablefloat.java
@@ -96,7 +96,7 @@ public class Nullablefloat implements Serializable, IGenericNullable {
 
 	@Override
 	public int hashCode() {
-		return Objects.hash(value);
+		return value == null ? 0 : value.hashCode();
 	}
 
 	@Override
diff --git a/src/main/java/it/cavallium/data/generator/nativedata/Nullableint.java b/src/main/java/it/cavallium/data/generator/nativedata/Nullableint.java
index 9bcf87f..90526c3 100644
--- a/src/main/java/it/cavallium/data/generator/nativedata/Nullableint.java
+++ b/src/main/java/it/cavallium/data/generator/nativedata/Nullableint.java
@@ -96,7 +96,7 @@ public class Nullableint implements Serializable, IGenericNullable {
 
 	@Override
 	public int hashCode() {
-		return Objects.hash(value);
+		return value == null ? 0 : value.hashCode();
 	}
 
 	@Override
diff --git a/src/main/java/it/cavallium/data/generator/nativedata/Nullablelong.java b/src/main/java/it/cavallium/data/generator/nativedata/Nullablelong.java
index 660bef9..a2b26c9 100644
--- a/src/main/java/it/cavallium/data/generator/nativedata/Nullablelong.java
+++ b/src/main/java/it/cavallium/data/generator/nativedata/Nullablelong.java
@@ -96,7 +96,7 @@ public class Nullablelong implements Serializable, IGenericNullable {
 
 	@Override
 	public int hashCode() {
-		return Objects.hash(value);
+		return value == null ? 0 : value.hashCode();
 	}
 
 	@Override
diff --git a/src/main/java/it/cavallium/data/generator/nativedata/Nullableshort.java b/src/main/java/it/cavallium/data/generator/nativedata/Nullableshort.java
index 316363b..11ae246 100644
--- a/src/main/java/it/cavallium/data/generator/nativedata/Nullableshort.java
+++ b/src/main/java/it/cavallium/data/generator/nativedata/Nullableshort.java
@@ -96,7 +96,7 @@ public class Nullableshort implements Serializable, IGenericNullable {
 
 	@Override
 	public int hashCode() {
-		return Objects.hash(value);
+		return value == null ? 0 : value.hashCode();
 	}
 
 	@Override