Tested on Windows-Xp Prof.
From Mustang Build 63, File.get{Free,Total,Usable}Space() throws NPE if a file is created in the current directory using new File("ram").createNewFile(). It has not been mentioned in the spec that File.getXXXSpace() methods throws NullPointerException. It should return size of the partition as the file is physically present as specified in the spec.
 
It is observed that File.getXSpace() throws NPE only if File Object is created like
File f =new File("ram");
f.createNewFile ();

File.getXSpace() works fine if File Object is created like
 1) File f = new File ("..\\ram");
    f.createNewFile();
 2) File f = new File("c:\\work\\BugVerification\\ram");
    f.createNewFile ();
 3) File f = new File (".","ram");
    f.createNewFile()

Please see the following code, version and Result.
<Code>
import java.io.File;
import static java.lang.System.out;

class Test {
public static void main(String[] args) {
          try {
               File file = new File("ram");
               out.println("File Created : " + file.createNewFile());
               out.println("File exists = " + file.exists());
               out.println("Absolute path of the file "+ file.getAbsolutePath ());
               out.println("Total space " + file.getTotalSpace());
               out.println("Free space " + file.getFreeSpace());
               out.println("Usable space " + file.getUsableSpace());
          } catch (Exception e) {
              e.printStackTrace();
          }
       }
}
</Code>
<Result-on-windows>

<build-61>

<version>
C:\work\BugVerification>c:\windows-i586\61\jdk1.6.0\bin\java -version
java version "1.6.0-rc"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.6.0-rc-b61)
Java HotSpot(TM) Client VM (build 1.6.0-rc-b61, mixed mode)
</version>

<Result>

C:\work\BugVerification>c:\windows-i586\61\jdk1.6.0\bin\java Test
File Created : true
File exists = true
Absolute path of the file C:\work\BugVerification\ram
Total space 0
Free space 0
Usable space 0

</Result>
</build-61>

<build-63>

<version>
C:\work\BugVerification>c:\windows-i586\63\jdk1.6.0\bin\java -version
java version "1.6.0-rc"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.6.0-rc-b63)
Java HotSpot(TM) Client VM (build 1.6.0-rc-b63, mixed mode)
</version>

<Result>

C:\work\BugVerification>c:\windows-i586\63\jdk1.6.0\bin\java Test
File Created : true
File exists = true
Absolute path of the file C:\work\BugVerification\ram
java.lang.NullPointerException
        at java.io.WinNTFileSystem.getSpace0(Native Method)
        at java.io.WinNTFileSystem.getSpace(WinNTFileSystem.java:39)
        at java.io.File.getTotalSpace(File.java:1576)
        at Test.main(Test.java:11)

</Result>
</build-63>
</Result-on-windows>