In Eclipse (I am running 3.8.0 @ Linux (Mint 14 (Ubuntu (Debian))) at the moment), renaming variables using Refactor is an option that seems random
You can always use Ctrl + 2 + R (Press R after appearing a small dropdown) to refactor the variable... [ Got it by chance ].
Update
working on Eclipse Neon... can't say about other older version. because it is the latest stable version at the time I am writing the answer.
Update 3-May-2017
one drawback is that it replaces all occurrences of that variable in the file. special care is required.