--- a/jdk/src/java.base/share/classes/jdk/internal/jrtfs/JrtFileSystemProvider.java	Wed Jul 05 21:36:10 2017 +0200
+++ b/jdk/src/java.base/share/classes/jdk/internal/jrtfs/JrtFileSystemProvider.java	Mon Apr 18 10:57:11 2016 -0700
@@ -101,10 +101,10 @@
     @Override
     public FileSystem newFileSystem(URI uri, Map<String, ?> env)
             throws IOException {
+        Objects.requireNonNull(env);
         checkPermission();
         checkUri(uri);
-
-        if (env != null && env.containsKey("java.home")) {
+        if (env.containsKey("java.home")) {
             return newFileSystem((String)env.get("java.home"), uri, env);
         } else {
             return new JrtFileSystem(this, env);