Simple way to detect unused properties keys?

Question

Given a set of properties files and list of files which may reference keys in those properties files, what's the easiest way to determine which keys are unused?

Example:

Given a project with files

muppets.properties

kermit=Kermit the Frog
oscar=Oscar the Grouch

smurfs.properties

papa=Papa Smurf

and /WEB-INF/pages/template.jsp

Some jsp template displaying the key <bean:write bundle='muppets' key='kermit'/>.

then running program with inputs "*.properties" and "/WEB-INF/**/*.jsp" should report

Unused properties:

muppets.properties
oscar

smurfs.properties
papa

What's the simplest way to do this? Are there any open-source Java libraries that make this easy? The idea is to embed the solution inside an in-house Maven reporting plugin that would run when building a web app.

I'm aware that there will be false positives (key strings appearing in the files in a non-key context), but that's ok. Being able to find any unused keys would be helpful.

Edit: I'm seeking a standalone code-base solution.

Answer 1

See also this question: The Halting Problem in the field

Answer 2

I'm also interested in such a feature. My solution for now is to just use the search function of eclipse to check my project if there is a key anywhere. It would be great if this could be done automaticly.

Answer 3

I think that JInto can help you.

http://www.guh-software.de/jinto%5Fen.html