To not load an applet just prevent it from running.
If the indicator is coded in to the application and the application does not give you an option to remove the indicator from the panel you wont be able to omit it, you cannot omit an application indicator that is build in to the code and has no option to disable it, for that you need source code changes either made by you or you can suggest them to the app developer, which is the last case will be depend on which applications your are referring to.
There are no specific guidelines explaining if and application should or should not have an inductor applet, only what an indicator applet should do.
You can still remove the system applets made by gnome for you system or if the application it self uses an external applet to be used as a indicator.
To remove one of the gnome / unity indicators that are visible by default open the terminal and run this command to show all the applications that can be loaded at start up
cd /etc/xdg/autostart/ && ls
Identify the applet that you want to prevent from loading and edit it with your favorite text editor, ie:
sudo nano nm-applet.desktop
Locate the line with these contents
NoDisplay=true
and change it to
NoDisplay=false
Save and close the terminal.
Click the cog weel in the top right corner of the screen next to your username and select Startup Applications...
, now you will see the application that you just edited the .desktop file and you can disable it.
The applet wont load on next boot
After enabling or disabling and applet following the steps above you will see that each .desktop that you modify will create it's own .desktop file in your ~/.config/autostart
folder.
If an applet indicator that you want to disable does not show on your startup list you need to use the method above, else there will be a .desktop file inside ~/.config/autostart
that can be edited with the described method and will then be possible to enabled/disabled in the startup applications.
This will work for versions 12.04 and above in case after installing Dropbox from their site using the DEB package, the icon does not show in Unity.
Remove Dropbox if already installed
sudo apt-get remove dropbox
Install the nautilus-dropbox package
sudo apt-get install nautilus-dropbox
In the case the steps above still do not work do the following (This package should already be installed but just in case):
sudo apt-get install libappindicator1
You will now need to restart Nautilus. You can either logout and then login or simply Reboot the PC.
The end result should be something like:
Tested on 12.04, 12.10, 13.04 and 13.10.
Best Answer
For Java Apps:
Actually for JDownloader case, It's a modular design. Tray icon comes as a plugin that can be disabled from:
JDownloader → Addons → Addon Manager → Extensions → Uncheck Activate box for JD Light Tray
For Java applications general case, It is possible to use Java security manager by writing a custom policy rules.
Create
java.policy
file in~/.jdownloader
contains:Modify
jdownloader
launch script to use custom policyAdd:
-Djava.security.manager -Djava.security.policy=java.policy
to java command call:These are the minimum rules that allowed me to launch jdownloader. You may need to add more permissions. Because there is no
deny
option you have to write all neededgrant
rules.References:
java.awt
: Class SystemTrayjava.awt
: Class AWTPermissionjava.security
: Class BasicPermissionSee Direct Known Subclasses if you want to write a general template that grant
AllPermission
exceptaccessSystemTray
. So you can use it for all remaining java apps.BTW, try to comment one of the rules by adding
//
to the beginning of line; So you can see how the error of denied permissions looks like. It tells you which permission you should to add. Also notice that I have used many-
&*
trying to extend rules as I'm looking for a quick solution (default wasAllPermission
anyway) and I'm not looking to jail the application.Here is a template to start with, trying to grant all possible permissions:
Note:
Java Policy Tools is a GUI tool to edit policy files. It make it more easy t find out all available options from drop box. It should be already install with Java package.