I am using Elementary OS, based on Ubuntu 12.04 and Eclipse Luna. The background color of javadoc popups is black and font color is dark grey, so it is unreadable. I tried to change background in eclipse preferences, but it did not change. Then I used google, and found solution, that I need to change tooltip bg color. So I did it. But still no change. Anyone knows how to change that color ?
I had the same problem with Ubuntu 16.04 and Eclipse Mars. I solved the problem by adding the following lines in eclipse.ini :
--launcher.GTK_version
2
As a KDE user, you have to change the tooltip background color with System Settings. Navigate to
Application Apperearence -> Colors (Left side menu) -> Colors (Colors tab on right side)
and adjust the Tooltip Background and Tooltip Text colors. In your case, adjusting the tooltip background should be enough.
The setting is under GNOME UBUNTU in Settings.
来源：https://stackoverflow.com/questions/28879560/eclipse-black-background-in-javadoc-popup