Currently loss of unsaved files may be a serious problems for users working with
Netbeans using X Window over a network or having source directories over NFS.
The solution might be appending all unsaved files on Netbeans shutdown or on
explicit user request to a configured backup file or directory. The file might
be located somewhere locally, in case of NFS problems etc. The default location
might be the .netbeans directory or the directory with temporary files. On
restart of Netbeans, a user would be notified about the location of the backed
up files.

The back up might be asynchronous with other IO operations, so it would still
work in case if the main thread terminates or Netbeans waits for NFS operations.