review: protect FileChooser return from internal NPE

[David Hill]

Kevin,

protect FileChooser return from internal NPE

https://bugs.openjdk.java.net/browse/JDK-8163526

inline in jbs.

Tested with a problem reproducer on windows.

-- 
David Hill<David.Hill at Oracle.com>
Java Embedded Development

"A man's feet should be planted in his country, but his eyes should survey the world."
-- George Santayana (1863 - 1952)