When using Java 8 Stream API, is there a benefit to combining multiple map calls into one, or does it not really affect performance?
For example:
stream.map(SomeClass::operation1).map(SomeClass::operation2);versus
stream.map(o -> o.operation1().operation2());1 Answer
The performance overhead here is negligible for most business-logic operations. You have two additional method calls in the pipeline (which may not be inlined by JIT-compiler in real application). Also you have longer call stack (by one frame), so if you have an exception inside stream operation, its creation would be a little bit slower. These things might be significant if your stream performs really low-level operations like simple math. However most of the real problems have much bigger computational cost, so relative performance drop is unlikely to be noticeable. And if you actually perform a simple math and need the performance, it's better to stick with plain old for loops instead. Use the version you find more readable and do not perform the premature optimization.
