> The cost of each new field is rarely considered

Most developers, in Java and in most other languages, do not consider the cost of every field, but I can tell you that people who need micro-optimisations certainly do care, and in Java's standard library, a layout is very much a concern (except, as always, you want to optimise what really matters; there's no point in optimising something that is unlikely to be a hot spot in a real program). Sometimes, though, you want to intentionally spread out the layout to avoid cache line sharing when concurrency is involved. You will find such examples in the standard library, too.

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re-thc an hour ago | parent [-]

> Most developers, in Java and in most other languages, do not consider the cost of every field

Are you saying most developers are bad? It’s the equivalent of most employees don’t consider the cost of every action to the employer and is how company spend blows up.

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pron 38 minutes ago | parent | next [-]

I'm saying that most developers aren't writing code where layout is a primary contributor to the program's performance. Even in performance-sensitive applications, only a minority of the team are working on the hot spots.

And speaking about costs, knowing what to optimise is the key to software performance. Improving the performance of an operation by 10000x will improve the performance of your program by less than 1% if the operation is only 1% of the profile to begin with. So I'm only saying that most developers don't work on code where the layout is very significant, but some certainly do.

	▲	re-thc 29 minutes ago \| parent [-]
		> I'm saying that most developers aren't writing code where layout is a primary contributor to the program's performance. I've heard this theory before. This isn't just about performance and I don't buy it. I've seen too many examples of this is just a temporary solution so it doesn't matter. >3 years later that "temporary solution" was still there and at the heart of many operations yet it's now to hard and too costly to fix. I've also seen the this is a quick hack. No 1 uses it. It doesn't go through any hot paths. All good. You know what happens? Years later, every service literally goes through it. Again, it's too hard to fix. In the real world these "theories" are really loose. The only fix is every should be aware of what they are doing and do it properly. The it might not happen, etc mindset is dangerous.

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Retr0id 41 minutes ago | parent | prev | next [-]

Most likely they just have other priorities. A lot of code is not at all performance-sensitive, or is bottlenecked by some other factor.

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nathanielks an hour ago | parent | prev | next [-]

If the previous commenter won't say that, I will

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LoganDark 21 minutes ago | parent | prev [-]

It doesn't take a "bad developer" to not consider the cost of every field...