Android Character.getNumericValue returns -1

I'm programming for Android and I'm using Character.getNumericValue but it's returning negative for space (' ', ASCII #31) and the exclamation mark ('!', ASCII #33) and likely the others that I haven't checked yet. Why isn't it returning the proper ASCII value?

What numeric value does ' ' have? Are you using the right method or technique to get its value?

Never mind, I can just use type-casting to convert char to int.