Is there an Eclipse plug-in to mark code, as with a highlighter pen. Anyone know if this is possible?
You could mark the line you want to highlight with a bookmark and then set a background color to highlight the bookmark.
You have to go in : preferences -> General -> Editors -> Text Editors -> Annotations
and then set the Text as highlighted with your preferred color :
I don't know of any such plug-in - I also searched Eclipse marketplace and Google for that.
However, if you have some experience with Eclipse plug-in development, writing an Eclipse command that creates an annotation for the selected text in the current editor should not be too hard (at least for your own use).
I usually use //TODO
. It gives a nice visual bookmark type thing which you can use to jump easily.