Good way to obfuscate code!

  boolean isDiskFull() {
    someReallyStupidSideEffect();
    return(diskFullness);
  }
  
  regularRoutine() {
    if(isDiskFull()); {
      //doErrorHandling in here
    }
  }

Best part about this code? The error handling will always execute, and some side effect will always happen.

I'm not sure I would have allowed the semi colon after an if (or while, or for) without an in between statement - I probably would have required the {} for an empty statement. (Though legitimately, ';' is a statement!)