If I want to make sure the input string is a valid number. It can be integer or double, with or without decimal. it can allow a "+" sign in front of it. But it can not be zero or negative. Of course it has to be a number (can't be string or char or things like that). what's the best way to validate this ?
There may be several possibilities,
In my opinion
1. Accept the input as string and then perform all the validations in pure java.
2. Make use of regex (regular expressions).