take this this works fien.. run this and enjoy
String temp_arr[];
File srcFolder = new File("D:\\temp\\");
srcFolder.list();
temp_arr = srcFolder.list();
Arrays.sort(temp_arr, String.CASE_INSENSITIVE_ORDER);
for(int i=0 ; i<temp_arr.length; i++)
System.out.println(temp_arr[i]);