Question

Is there any reason to use Integer.valueOf(X) to initialize a final Integer, as below:

public class MyClass
{
  public static final Integer DAY_1 = Integer.valueOf(1); // Why do it this way?
  public static final Integer DAY_2 = 2; // When it can be done this way?
}

I understand this was necessary in older versions of Java before autoboxing was added. Does any reason for this type of code remain? Or is it just a bad habit?

Answer 1

• There’s a lot of code written before 1.5 came out. There’s no need to update it all without bringing any benefit.
• In some cases it makes it clearer that you are boxing. In the case you gave you can easily see the target type on the same line – but that’s not always the case.
• If you want to call a method which has overloads for both Integer and int and you want to call the Integer overload, this is an easy way to do it.