Extract all string from a java project

Question

I have a rather big number of source files that I need parse and extract all string literals and put them in a file as play old java constant.
For exemple:

Answer 1

To complete Peter Kelley answer, you might consider for eclipse IDE the AST solution.

You might then write an AST program which parse your source code and does what you want.

A full example is available in this eclipse corner article, also more details in the eclipse help.
And you can find some examples in Listing 5 of the section "Implementation of in-place translation" of Automating the embedding of Domain Specific Languages in Eclipse JDT, alongside multiple examples in GitHub projects.