You did not get that failure mode. If you want to fail at file not found, wrap it in a RuntimeException or IllegalStateException or something. You don't even have to create a new class, just use one of these 2 built ito Java.

For example: you store a conversion factor in you config file (eurostodollars=1.12 or whatever).

If you have an empty catch block, you now have a null Reader object or something. Next read will throw an IOException, which you also swallow and you now have an uninitialized config value. Except that one will be zero instead of null.

500 km further in your code, a month after you started the app, that zero gets used in your code.

  amounttopay+=eurostodollars*euroamount;

This will not fail immediately either. No, it will do something weird. In the best case, you crash for a really weird reason. More probably, you send out a file or web call or ... with insanely wrong data. Bonus points if you sign it with a private key, then you're legally bound by whatever nonsense you happened to promise. The next program in the chain might sit either in your company or not. It will swallow your garbage date wholly, do no checking of its own as this no-error-checking culture is pervasive. It will either crash and or do further damage. When the shit finally hits the fan, it will be a containerload of shit instead of a mouse dropping.

I saw this kind of scenario again and again. No , the app cant possibly start without database, that never happens, and anyway the next user will notice the empty database. Except after power failure in the middle of the night, when the database is still booting up while your app is reading the config from it. When business hour start, everything seems fine. Until it isnt.