gistfile1.txt

public class Casting {
    public static void main(String[] args) {

        // Those below are objects that get autoboxed automatically
        Integer i = 0;
        Long l = 0L;
        Double d = 0D;
        Float f;
        
        Float f2 = 1f;

        f = (float) d; // This you are getting an object and trying to cast to a primitive of different type
        f = (float) f2; // This sucks! It probably is the reason of confusion...
        f = (float) (double) d; // This works because you are unboxing the Double object "(double) d" then casting to float

        f = (float) d.doubleValue(); // This works!

        f = d.floatValue(); // And this too, of course

        
   }
}