I’m thinking about making an object that consists of a large grid, stored in a two dimensional array, and functions that work on that grid.
If I want to iterate through the elements in this array outside of the object, the most readable and privacy-respectful way to access each grid element would be to use a function like grid.getElement(x,y), which simply returns array[x][y].
When the program is compiled into bytecode, is this any less efficient than directly accessing the array by means of grid.array[x][y]?
It’s potentially less efficient, but it depends on your JVM. A good JIT may be able to inline the function, thereby making the code exactly equivalent.
The only way to know for sure is to benchmark with the JVM that you’ll be using. Before you even do that you should verify that it even matters. (ie: profile then optimize) Unless your profiling tells you that a particular piece of code is a bottleneck, go with the cleanest design, and don’t try to micro-optimize like this. There’s a good chance that it wouldn’t buy you any measurable performance gain anyway, and it’ll definitely make your code harder to maintain.