java - NullPointer Exception while read audio files -

i made program read audio files. @ first did absolute path because it's easyer develop.
then cahnge relative path because want compress *jar. code method(at first short later code:

1.: @ first make filearray save files 2.: make array save audioclip 3.: loop read clips 

now code:

    private audioclip[] liesaudiodateien (file inputfile) {         file[] datefilearray;         audioclip[] tracks;         datefilearray = inputfile.listfiles();         tracks = new audioclip[datefilearray.length];         (int = 0; < tracks.length; i++) {             if (datefilearray[i].isfile()) {                 try {                     tracks[i] = applet.newaudioclip(datefilearray[i].tourl());                 } catch (ioexception ex) {                     system.err.println("error!: -- " + ex.tostring());                 }             }          }         return tracks;        } 

inputfile.listfiles() returns null, seems path isn't ok. path ok, because let print on command line. d:\eclipse\myprojekt\dist\myproject.jar\audio. in netbeans, work. if make jar file, doesn't work.

i have try:

1. d:\eclipse\myprojekt\dist\myproject.jar\audio\
2. / in place of \

are sure correct file path?

d:\eclipse\myprojekt\dist\myproject.jar\audio 

the audio directory in folder called myproject.jar?

if audio files within .jar file cannot use file class list them. have instead read entries .jar file, in question.