unboxing - how it becomes a better way to explicitly use intValue() compared to unboxing by itself

Question

I was reading O'REILLY Java8 pocket guide when I came across this advise about unboxing [On page 30]

Note: For these examples, primitive variables end with a capitalP. This is not the convention.

The following example shows an acceptable but not recommended use of unboxing

Establish the weight allowance

weightLimitP = weightLimitP + weightAllowanceW;

It is better to write this expression with the intValue() method, as shown here:

weightLimitP = weightLimitP + weightAllowanceW.intValue();

Question: What I would like to know here is why is the second approach a better way? I mean, in what terms is it 'better'. How is it different from unboxing by itself

Note: The wrapper class in this example is Integer

Surely the pocket guide said something about why the author thinks it's "better"? — T.J. Crowder, Jun 17 '16 at 08:25
I'd double-check if I were you. I normally expect better of O'Reilly (even in a pocket guide). — T.J. Crowder, Jun 17 '16 at 08:28
From Java 5 onward, those two code snippets will generate [exactly the same bytecode](http://stackoverflow.com/questions/6915823/which-is-better-in-terms-of-performance-implicit-auto-unboxing-or-explicit-un). So "better" is purely a matter of style, which is opinion-based. Also related: http://stackoverflow.com/questions/9331059/getting-intvalue-from-integer-does-it-make-any-sense, http://stackoverflow.com/questions/15985928/what-is-the-need-of-an-intvalue-method-if-wrappers-use-unboxing — T.J. Crowder, Jun 17 '16 at 08:29
Only difference is writing style. both the codes are equal in terms of bytecode. — Sanjeev, Jun 17 '16 at 08:31
Thank you @T.J.Crowder for the relative links and explanation. — spiderman, Jun 17 '16 at 09:07

score 1 · Accepted Answer · edited May 23 '17 at 12:08

1

Those two code snippets will generate exactly the same bytecode. So "better" is purely a matter of style and, thus, opinion.

edited May 23 '17 at 12:08

Community

1
1

answered Jun 17 '16 at 09:09

T.J. Crowder

1,031,962
187
1,923
1,875

score 1 · Answer 2 · answered Jun 17 '16 at 09:23

It compiles to the same code. But it might be considered to be better style. Reason: one now can see at one glance that a NullPointerException might be raised or that it is a wrapper class, and a primitive class would be better.

This to the adage that code is read more often than written.

unboxing - how it becomes a better way to explicitly use intValue() compared to unboxing by itself

2 Answers2