[arvidjonasson]

This is a breaking change. Makes IntArrayList (and LongArrayList) skip bounds checking when agrona.disable.bounds.checks is set to true, which is the same parameter as in DirectBuffer. Bounds checking is not completely gone because there is still the implicit 0 <= index < elements.length bounds check inserted by the JVM when indexing arrays, but it reduces the the number of bounds checks from 2 to 1 (the C2 JIT was never smart enough to deduplicate the bounds checks).

[vyazelenko]

agrona.disable.bounds.checks is a setting for DirectBuffer and has nothing to do with collections. Explicit index checks is what JDK collections have as well. Those additional branches should be well predicted by the CPU and cost virtually nothing.

[arvidjonasson]

In my testing, removing the bounds checking made getInt between 30% to 59% faster (depending on the array size) even when the function had only ever taken one branch. Would you consider adding a property to remove bounds checking for IntArrayList?

[vyazelenko]

@arvidjonasson Can you provide a benchmark that demonstrates the huge performance cost of the index checking?

P.S. I've pushed a change (9b5c189) where the custom index was replaced with java.util.Objects.checkIndex(int, int) call. This is what java.util.AbstractList and friends are using.