Iterative vs Recursive Merge Sort in TheAlgorithms Java: Stack Safety versus Simplicity

When sorting large arrays with TheAlgorithms Java merge sort implementations, developers must decide between the recursive version (MergeSort.java) and the iterative version (MergeSortIterative.java). The recursive variant offers concise, easy‑to‑read code but uses O(log n) call‑stack depth, which can exceed the JVM thread limit and throw a StackOverflowError for inputs larger than roughly one million elements, depending on stack size. The iterative variant replaces deep recursion with an explicit loop and a temporary array, preserving O(n) time and O(n) auxiliary space while guaranteeing stack‑safe execution for arbitrarily large inputs. However, licensing headers differ between the two files and the repository does not provide a unified recommendation or performance benchmark, leaving the choice to the developer’s judgment.

Given these trade‑offs, what factors should weigh most heavily when selecting an implementation for production code that may encounter inputs beyond the typical stack limit? Are there scenarios where the recursive version’s simplicity justifies the risk of a StackOverflowError, perhaps with safeguards such as increasing thread stack size? How does the varying licensing affect the decision when integrating the code into a proprietary project?