Java-Generic Constructors

Generic Constructors

It is possible for constructors to be generic, even if their class is not. For example, in the following program, NumberToInt constructor specifies a parameter of a generic type, which must be a subclass of Number, NumberToInt constructor can be called with any numeric type, including Integer, Float, or Double. Therefore, even though NumberToInt is not a generic class, its constructor is generic. Notice that NumberToInt constructor calls look like normal constructor calls. Generic constructor also infer its type from its  arguments.

Program

class NumberToInt {

     <T extends Number> NumberToInt(T t) {

        int x = t.intValue();
        System.out.println("T -> "+t.getClass().getName());
        System.out.println("Int x = " + x);
    }
}

public class Javaapp {

    public static void main(String[] args) {

        NumberToInt fti = new NumberToInt(45.67f);
        NumberToInt dti = new NumberToInt(67.67d);
    }
}