Neither knowing C nor knowing the lower-level details of implementation hurt you — in themselves. What can and will hurt you is if you consistently think and work in terms of the low-level details, even when it’s inappropriate. The old saying was that “real programmers can write FORTRAN in any language.” If you do the … Read more
It is very much dependent on the underlying architecture, but any difference will be minuscule. If anything, I’d expect (x >= 0) to be slightly faster, as comparison with 0 comes for free on some instruction sets (such as ARM). Of course, any sensible compiler will choose the best implementation regardless of which variant is … Read more
No, it’s not true. You could measure the performance by timing each loop for a large number of iterations, but I’m fairly certain they will be the same. The myth came from C where ++i was regarded as faster than i++ because the former can be implemented by incremeting i then returning it. The latter … Read more
No, a call to array.length is O(1) or constant time operation. Since the .length is(acts like) a public final member of array, it is no slower to access than a local variable. (It is very different from a call to a method like size()) A modern JIT compiler is likely to optimize the call to … Read more
There’s only one type of “if” statement there. The other is a conditional expression. As to which will perform better: they could compile to the same bytecode, and I would expect them to behave identically – or so close that you definitely wouldn’t want to choose one over the other in terms of performance. Sometimes … Read more
Don Knuth started the literate programming movement because he believed that the most important function of computer code is to communicate the programmer’s intent to a human reader. Any coding practice that makes your code harder to understand in the name of performance is a premature optimization. Certain idioms that were introduced in the name … Read more
First: you shouldn’t be making the choice of static vs non-static on the basis of performance. Second: in practice, it won’t make any difference. Hotspot may choose to optimize in ways that make static calls faster for one method, non-static calls faster for another. Third: much of the mythos surrounding static versus non-static are based … Read more