feat: add JSpecify @NullMarked annotations for null-safety

Author: mariuszs

friendly-id/pom.xml

@@ -16,6 +16,11 @@
     <description>Core library for converting UUIDs to URL-friendly Base62-encoded IDs</description>
 
     <dependencies>
+        <dependency>
+            <groupId>org.jspecify</groupId>
+            <artifactId>jspecify</artifactId>
+            <version>1.0.0</version>
+        </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>

friendly-id/src/main/java/com/devskiller/friendly_id/package-info.java

@@ -0,0 +1,10 @@
+/**
+ * FriendlyId - URL-friendly Base62 encoding of UUIDs.
+ * <p>
+ * This package is null-marked, meaning all parameters and return values
+ * are non-null by default unless explicitly annotated with {@link org.jspecify.annotations.Nullable}.
+ */
+@NullMarked
+package com.devskiller.friendly_id;
+
+import org.jspecify.annotations.NullMarked;

friendly-id/src/main/java/com/devskiller/friendly_id/type/package-info.java

@@ -4,8 +4,15 @@
  * This package provides type-safe, memory-efficient value objects for working with FriendlyIds
  * in domain models and persistence layers.
  * </p>
+ * <p>
+ * This package is null-marked, meaning all parameters and return values
+ * are non-null by default unless explicitly annotated with {@link org.jspecify.annotations.Nullable}.
+ * </p>
  *
  * @see com.devskiller.friendly_id.type.FriendlyId
  * @since 1.1.1
  */
+@NullMarked
 package com.devskiller.friendly_id.type;
+
+import org.jspecify.annotations.NullMarked;