|| what is jdownloader
please take a look this

|| how to install jdownloader on linux debian
| installing openjdk-6-jdk

# aptitude install openjdk-6-jdk

| installing jdownloader on current user home

$ mkdir bin
$ cd ~/bin
$ wget //212.117.163.148/jd.sh
$ chmod +x jd.sh
$ ./jd.sh

|| add jdownloader shortcut on panel
0. right-click gnome panel and select Add to Panel..
1. select Custom Application Launcher..
2. add value on Add Louncher, like:
Type: Aplication
Name: jDownloader
Command: /home/username/bin/jd.sh
3. click OK button

|| links
| google
| jdownloader