ResourceBundle Editor is an Eclipse plugin for editing localized properties files, aka resource bundles. It allows you to manage key/value information for all related properties files at once, through the same screen. No more flipping, and searching through files for keys or values to modify or otherwise deal with.
Keys are always sorted.
Can report missing, duplicate, and similar values.
Non-ASCII character conversion to/from Unicode.
Multiple properties file formating options (key grouping, line wrapping, etc).
Can toggle between flat and hierarchical view of keys.