Systray Icon class provides a convenient method to display a message, however I'd like to popup a arbitrary content, in my case I'd like to show a new song album art when an application is iconized mode. Generally it isn't look like a complicated task, I just want to verify: 1. systray icon doesn't support that 2. there is no open source solution around
Unfortunately, it doesn't look like there's an easy way to pop an image up from a TrayIcon currently.
You could try to do something like popping up a JWindow temporarily near the bottom of the screen, but I've played around with it some, and my attempts weren't completely satisfactory - there's no way to get the real location you should pop up the window - you just have to assume the task bar is at the bottom of the screen, and that there aren't a ton of icons in the system tray pushing your icon far to the left, and that the taskbar isn't taking up multiple rows, etc. You also have to handle all the timing logic to show/hide your window.