Localize your java Logger
Internationalize your java log messages almost for free.

Here's an example Foo.java:

  import java.util.logging.Logger;

  public class Foo {
    private static final Logger LOG
      = Logger.getLogger(Foo.class.getName(),
                         Foo.class.getName());

    public static void main(String[] a) {
       LOG.info("Everything is dandy."); // old way
       LOG.info("dandy");                // new way
    }
  }

Create a Foo.properties file with this line

   dandy=Everything is dandy.

in the same directory as Foo.class.

You'll see the same message twice.

Or create Foo_hick.properties with

   dandy=Boy howdy.

and run

   java -Duser.language=hick test.Foo

(Real languages use two-letter codes like en, es, ch, fr.)