Fix StringIndexOutOfBoundsException parsing JTDS JDBC URLs without a database segment

[dougqh]

Summary

• JTDS.doParse() in JDBCConnectionUrlParser used dbLoc as the substring end index when parsing the port number, but dbLoc is -1 when the URL has a host:port with no trailing /database and no ;params (e.g. jdbc:jtds:sqlserver://host:1433) — this throws StringIndexOutOfBoundsException from String.substring.
• Compute the correct end index for the port substring: fall back to paramLoc (when there are ;params but no db) or details.length() (bare host:port) instead of blindly using dbLoc.
• Found while triaging a production stack trace showing this exception escaping DriverManager.getConnection up through JDBCDecorator.

Test plan

• Added regression cases to JDBCConnectionUrlParserTest.groovy: jdbc:jtds:sqlserver://dbhostname.com:1433 and jdbc:jtds:sqlserver://dbhostname.com:1433;user=user;password=pw
• ./gradlew :dd-java-agent:instrumentation:jdbc:test --tests JDBCConnectionUrlParserTest passes
• Ran /techdebt — no issues found

🤖 Generated with Claude Code

[datadog-prod-us1-6]

🎯 Code Coverage (details)
• Patch Coverage: 0.00%
• Overall Coverage: 61.86% (+3.51%)

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[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	13.96 s	13.91 s	[-0.4%; +1.1%] (no difference)
startup:insecure-bank:tracing:Agent	12.89 s	12.96 s	[-1.4%; +0.3%] (no difference)
startup:petclinic:appsec:Agent	17.41 s	17.12 s	[+0.7%; +2.6%] (maybe worse)
startup:petclinic:iast:Agent	16.69 s	17.44 s	[-8.4%; -0.2%] (maybe better)
startup:petclinic:profiling:Agent	17.33 s	17.37 s	[-1.5%; +1.1%] (no difference)
startup:petclinic:sca:Agent	17.48 s	17.23 s	[+0.6%; +2.3%] (maybe worse)
startup:petclinic:tracing:Agent	16.15 s	16.59 s	[-6.8%; +1.5%] (no difference)

Commit: ee9d2850 · CI Pipeline · Benchmarking Platform UI

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