Question

A simple design question.

Sample code:

    Integer int1 = new Integer(20);     
    System.out.println(Integer.toBinaryString(int1));

Why JDK design is not something like the following? so, toBinaryString function returns the the desired result?

    System.out.println(int1.toBinaryString());

Aside for wide usability of a static function, what are the other reasons for this design approach? Are they using any particular design pattern? If it is then, which pattern?

Answer 1

Your sample code creates an instance of Integer and then unboxes it. There’s no need for that:

int int1 = 20;
String binary = Integer.toBinaryString(int1);

If it were an instance method, you’d be forced to create an instance of Integer solely to convert an int to its binary representation, which would be annoying.

In other words: to avoid creating objects unnecessarily.