Whenever the type set to be created is fixed, as the latest two comments have noticed, a more specific approach is probably better, but this one IMHO wins when generality is required.

The downside of the funky solution is that its is very inefficient. I have one helper method which does this ugly, but efficient way and I call that, and so hides the “crappy” way.

If you want to support conversion of other types you may find that the String constructor is either not there or doesn’t do what you would want.

Useful text conversions include Enum, and DateTime,a dn you can support String[], Integer[], List, Map

I prefer to use the caches for Boolean, Integer, Long rather than creating new object every time.

I treat “NaN” as NaN, and empty String as null in most cases.

You’re circumventing caches, using reflection for simple lookups and giving up proper exceptions. Probably more, but I stopped counting.

Use java.text.NumberFormat for proper string to number conversions, and add a single check for Double.NaN.

Class number;
T zero = (T) number.getConstructor(String.class).newInstance(”0″);