[JAVA-4816] perf: improving performance of ObjectId parseHexString()

[eonwhite]

JIRA Ticket: https://jira.mongodb.org/browse/JAVA-4816

The current implementation of ObjectId parseHexString is somewhat slow, because it makes a total of 12 calls to Integer.parseInt, which is not the fastest to begin with. This imposes some overhead to all ObjectId(string) calls, which can really add up at scale, for example when deserializing a large amount of ObjectId data via Jackson.

Replacing this implementation with a hand-rolled version which converts each part of the hex string to a byte. This in my rough testing is about 5x faster than the current implementation of parseHexString.

Tests (on my M1 MacBook Pro):

    public static void main(String[] args) {
        long startTime = System.currentTimeMillis();
        for (int i = 10000000; i < 100000000; i++) {
            new ObjectId("1234567890abcdef" + i);
        }
        long endTime = System.currentTimeMillis();

        System.out.println("Time elapsed: " + (endTime - startTime));
    }

On master:

Time elapsed: 19460

On branch:

Time elapsed: 3617

[jyemin]

Hi @eonwhite thanks for the contribution. Can you do a couple of things to move this forward:

1. Open an issue in the JAVA project of MongoDB's Jira, and then reference the issue number in the PR description (see the CONTRIBUTING guide for details). Please attach your performance tests as well.
2. Run ./gradlew bson:check to make sure all static and runtime checks are passing

[eonwhite]

Hi @eonwhite thanks for the contribution. Can you do a couple of things to move this forward:

1. Open an issue in the JAVA project of MongoDB's Jira, and then reference the issue number in the PR description (see the CONTRIBUTING guide for details). Please attach your performance tests as well.
2. Run ./gradlew bson:check to make sure all static and runtime checks are passing

Thanks @jyemin -- have resolved issues and verified that tests pass.

[jyemin]

Hi @eonwhite I pushed a commit with a few small improvements to your PR. PTAL and then I can merge it.

[jyemin]

Thanks again for the contribution @eonwhite