src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/resources/fx/base.js

@@ -106,9 +106,9 @@
         visitFileFailed: function(file, ex) {
             return CONTINUE;
         }
     });
 
-    Files.walkFileTree(rootDirectories[0], new JRTFSWalker());
+    Files.walkFileTree(rootDirectories.toArray()[0], new JRTFSWalker());
 })();
 
 LOAD_FX_CLASSES(this, "javafx.base");