--- a/jdk/src/java.base/share/classes/java/lang/module/ModuleReader.java	Wed May 25 19:58:03 2016 +0100
+++ b/jdk/src/java.base/share/classes/java/lang/module/ModuleReader.java	Wed May 25 20:12:32 2016 +0100
@@ -30,6 +30,7 @@
 import java.io.InputStream;
 import java.net.URI;
 import java.nio.ByteBuffer;
+import java.util.Objects;
 import java.util.Optional;
 
 
@@ -163,9 +164,12 @@
      * @param  bb
      *         The byte buffer to release
      *
-     * @implSpec The default implementation does nothing.
+     * @implSpec The default implementation doesn't do anything except check
+     * if the byte buffer is null.
      */
-    default void release(ByteBuffer bb) { }
+    default void release(ByteBuffer bb) {
+        Objects.requireNonNull(bb);
+    }
 
     /**
      * Closes the module reader. Once closed then subsequent calls to locate or