Since Eclipse Luna, dark theme is preinstalled in Eclipse. Currently is's far from perfect, but I will show you how to fine tune the theme. In the future fine tuning may not be necessary.
Also you can alternatively download from Eclipse Marketplace plugin Eclipse Color Theme and choose theme Monokai. It is also very nice dark theme.
Also be sure to backup your workspace directory, because it's the easiest way how to revert all changes done in this video if you're not satisfied with the result.
Anyway, let's use the default dark theme. To activate it go to Window -> Preferences -> General -> Appearance and select Theme: Dark.
If you are not satisfied with the result, continue. Goto Help -> Eclipse Marketplace and install Moonrise UI Theme. This is the latest version of Eclipse Dark theme. Again go to Window -> Preferences -> General -> Appearance and select Theme: MoonRise (standalone).
Again, if you're satisfied stop right there. Currently the syntax highlight is terrible. Go to MoonRise UI homepage: http://guari.github.io/eclipse-ui-theme/ and download RainbowDrops.epf. Next open File -> Import, select General -> Preferences and import the file.
If you have any issues with the theme, go to MoonRise UI theme homepage. Currently I'm satisfied with the result and really enjoy this beautiful theme, which doesn't hurt my eyes.
If you want to revert all changes done to editor colors (and you didn't backup workspace as I recommended), follow instructions in this post: http://stackoverflow.com/questions/4118632/revert-to-eclipse-default-settings
To have everything dark in Windows, see this blog post: http://www.makeuseof.com/tag/10-dark-windows-themes-skins-reduce-eye-strain/