Add javax.annotation.Nullable impl

Author: adrienlauer

CHANGELOG.md

@@ -1,5 +1,6 @@
 # Version 3.5.1 (2018-04-28)
 
+* [new] Add an implementation of `javax.annotation.Nullable` avoiding the need of an additional dependency for null injection. 
 * [chg] Remove the need for `jaxb-api` dependency for `seed-rest-jersey2` module under Java 9.
 
 # Version 3.5.0 (2018-03-16)

specs/src/main/java/javax/annotation/Nullable.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright © 2013-2018, The SeedStack authors <http://seedstack.org>
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+package javax.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/**
+ * The annotated element could be null under some circumstances.
+ *
+ * <p>
+ * Can be used on injection points to specify that injecting a null is allowed.
+ * </p>
+ */
+@Documented
+@Retention(RetentionPolicy.RUNTIME)
+public @interface Nullable {
+
+}