Add missing coverage tests for Hashtable.D2

[dougqh]

What This Does

Improves coverage of Hashtable

Motivation

Better test coverage

Additional Notes

• Add removeReturnsNullForMissingKey — remove() was only tested for the found case; the null-return path was uncovered
• Add clearEmptiesTable — clear() had no test at all

Test plan

• ./gradlew :internal-api:test --tests "datadog.trace.util.HashtableD2Test" passes

🤖 Generated with Claude Code

[dd-octo-sts]

🟢 Java Benchmark SLOs — All performance SLOs passed

Suite	Status
Startup	🟢 pass

SLO thresholds are defined here based on automatically generated metrics. A warning is raised when results are within 5% of the threshold.

PR vs. master results

Scenario	Candidate	master	Δ (95% CI of mean)
startup:insecure-bank:iast:Agent	13.92 s	14.02 s	[-1.6%; +0.1%] (no difference)
startup:insecure-bank:tracing:Agent	12.99 s	13.06 s	[-1.5%; +0.4%] (no difference)
startup:petclinic:appsec:Agent	16.91 s	16.87 s	[-0.5%; +1.0%] (no difference)
startup:petclinic:iast:Agent	16.89 s	16.93 s	[-1.0%; +0.6%] (no difference)
startup:petclinic:profiling:Agent	16.89 s	17.04 s	[-1.9%; +0.1%] (no difference)
startup:petclinic:sca:Agent	17.00 s	16.79 s	[+0.3%; +2.1%] (maybe worse)
startup:petclinic:tracing:Agent	16.03 s	15.61 s	[-1.6%; +7.0%] (no difference)

Commit:0c207443 · CI Pipeline · Benchmarking Platform UI

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Load and DaCapo benchmarks can be triggered manually in the GitLab pipeline. Results will appear in the Benchmarking Platform UI after completion.

[dd-octo-sts]

/merge

[gh-worker-devflow-routing-ef8351]

View all feedbacks in Devflow UI.

2026-06-29 16:24:24 UTC ℹ️ Start processing command /merge

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2026-06-29 16:24:29 UTC ℹ️ MergeQueue: pull request added to the queue

The expected merge time in master is approximately 1h (p90).

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2026-06-29 17:25:29 UTC ℹ️ MergeQueue: This merge request was merged