What is the output of this program ?

class Output
{
    public static void main(String args[]) 
    { 
        Integer i = new Integer(514);
        float x = i.floatValue(); 
        System.out.print(x);
    }
}

1. 0
2. 1
3. 257
4. 514.0

What are wrapper classes?

What is the need of wrapper classes when there are primitive datatypes ?

When do the numeric wrapper class constructors raise NumberFormatException ?