Most memory efficient way to grow an array in Java?

Question

I\'m not too concerned about time efficiency (the operation will be rare), but rather about memory efficiency: Can I grow the array without temporarily having all th

Answer 1

Arrays are constant-size, so there is no way to grow them. You can only copy them, using System.arrayCopy to be efficient.

---

ArrayList does exactly what you need. It's optimized much better than any of us could do, unless you devote a considerable time to it. It uses internally System.arrayCopy.

---

Even more, if you have some huge phases where you need the list to grow/reduce, and others where it doesn't grow/reduce and you make thousands of read or write in it. Suppose also you have a huge performance need, that you prooved that ArrayList is too slow when read/writing. You could still use the ArrayList for one huge phase, and convert it to an array for the other. Note this would be effective only if your application phases are huge.