src/java.base/windows/classes/java/io/WinNTFileSystem.java

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this

@@ -23,10 +23,12 @@
  * questions.
  */
 
 package java.io;
 
+import java.io.File;
+import java.nio.file.Path;
 import java.util.Locale;
 import java.util.Properties;
 import sun.security.action.GetPropertyAction;
 
 /**

@@ -625,10 +627,31 @@
 
     private native long getSpace0(File f, int t);
 
     /* -- Basic infrastructure -- */
 
+    // Obtain maximum file component length from GetVolumeInformation which
+    // expects the path to be null or a root component ending in a backslash
+    private native long getNameMax0(String path);
+
+    public long getNameMax(String path) {
+        String s = null;
+        if (path != null) {
+            File f = new File(path);
+            if (f.isAbsolute()) {
+                Path root = f.toPath().getRoot();
+                if (root != null) {
+                    s = root.toString();
+                    if (!s.endsWith("\\")) {
+                        s = s + "\\";
+                    }
+                }
+            }
+        }
+        return getNameMax0(s);
+    }
+
     @Override
     public int compare(File f1, File f2) {
         return f1.getPath().compareToIgnoreCase(f2.getPath());
     }