I want that my java program search for specific files in a selected folder that is select from jfilechooser if he found the files or file there should come a messagebox if not a other messagebox

Answer 1

To open a specific path with the file chooser:
http://stackoverflow.com/questions/13516829/jfilechooser-change-default-directory-in-windows
To filter specific files:
http://stackoverflow.com/questions/18575655/how-to-restrict-file-choosers-in-java-to-specific-files