Wanting to use the messages in ICU4J, I was lead to believe one needed to run the command:
This produces root.res.
However using the following snippet results in the error message below:
UResourceBundle urb = UResourceBundle.getBundleInstance("Your package path","root");
>Data file yourPackagePath/root.res is corrupt - ICU data file error: Header authentication failed, please check if you have a valid ICU data file