Description of problem:

The JNLP javadoc says that when retrieving the contents of a file, it must
trigger a FileNotFoundException if the store is not found, the current NetX
implementation return a dummy FileContents that later trigger the
FileNotFoundException when calling getInputStream(). This cause problems with
code that check if the store is created with the PersitenceService>>get() method
before calling getInputStream()

http://java.sun.com/products/javawebstart/1.0.1/javadoc/javax/jnlp/PersistenceService.html#get(java.net.URL)


Version-Release number of selected component (if applicable):
java-1.6.0-openjdk-1.6.0.0-0.15.b09.fc9.i386

Steps to Reproduce:
1.Clear all netx cache and .netx directory
2.Call PersistenceService>>get()
3.It must signal a FileNotFoundException because never has been created a
persistence store
  
Actual results:
No exception is thrown calling PersistenceService>>get(), only after calling
getInputStream()

Caused by: java.io.FileNotFoundException: [path to file here] (No such file or
directory)
	at java.io.FileInputStream.open(Native Method)
	at java.io.FileInputStream.<init>(FileInputStream.java:137)
	at
net.sourceforge.jnlp.services.XFileContents.getInputStream(XFileContents.java:68)
	... 20 more

Expected results:
FileNotFoundException when calling PersistenceService>>get() if the store has
not been created