Remove sqljdbc_xa.dll: drop legacy XA extended-procedure DLL

[Ananya Garg (Ananya2)]

Summary

Removes all references to the legacy server-side sqljdbc_xa.dll from the driver's documentation and diagnostics. XA distributed transactions now rely solely on the xp_sqljdbc_xa_* extended stored procedures that are built into SQL Server 2017 CU16 and later (enabled via EXEC sp_sqljdbc_xa_install). The DLL is no longer shipped.

Motivation

sqljdbc_xa.dll was only required for SQL Server 2016 and earlier — the sp_xa procedures have been built into the SQL Server engine since SQL Server 2017 CU16. The server-side sp_xa sprocs originally derived from the code in this JDBC DLL, so a recently reported MSRC vulnerability in the server procedures is likely to exist in the DLL as well. With SQL Server 2016 leaving the 5+5 support lifecycle this year, the DLL can be safely dropped rather than serviced.

Changes

• README.md — "Download the DLLs" no longer lists sqljdbc_xa; documents that XA procedures are built into SQL Server 2017 CU16+ (enable via sp_sqljdbc_xa_install) and that the standalone DLL is no longer shipped.
• DLLException.java — Class comment now references only the mssql-jdbc_auth DLL.
• XAStateTest.java — Diagnostic hints updated to point to EXEC sp_sqljdbc_xa_install on SQL Server 2017 CU16+.

Not changed (intentionally)

• SQLServerXAResource.java and the xp_sqljdbc_xa_* calls — the XA feature remains fully functional against SQL Server 2017 CU16+.
• R_failedToInitializeXA resource string and its localized translations.

Testing

No runtime code changed — only docs, one comment, and test diagnostic strings. XA tests continue to run against SQL Server 2017 CU16+ using the built-in stored procedures.

Related

Companion PR in the internal build repo removes the DLL source, build, and packaging.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 60.52%. Comparing base (a45b6cb) to head (ceb5972).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #3017      +/-   ##
============================================
+ Coverage     60.18%   60.52%   +0.33%     
- Complexity     5138     5251     +113     
============================================
  Files           153      153              
  Lines         36673    36679       +6     
  Branches       6733     6733              
============================================
+ Hits          22073    22201     +128     
+ Misses        10751    10742       -9     
+ Partials       3849     3736     -113     

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[Copilot]

Pull request overview

This PR updates the driver’s documentation and diagnostic messaging to remove outdated guidance about installing sqljdbc_xa.dll, aligning XA setup guidance with SQL Server 2017+ built-in XA stored procedures enabled via sp_sqljdbc_xa_install.

Changes:

• Updates README XA guidance to remove sqljdbc_xa DLL installation instructions and point users to EXEC sp_sqljdbc_xa_install on SQL Server 2017+.
• Updates DLLException class comment to reference only the mssql-jdbc_auth DLL.
• Updates XA state machine test diagnostic strings to reference enabling XA via sp_sqljdbc_xa_install.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
README.md	Removes outdated sqljdbc_xa DLL instructions and adds SQL Server 2017+ XA enablement guidance.
src/main/java/com/microsoft/sqlserver/jdbc/DLLException.java	Updates comment to remove sqljdbc_xa DLL mention.
src/test/java/com/microsoft/sqlserver/jdbc/statemachinetest/xa/XAStateTest.java	Updates diagnostic output/hints to reference sp_sqljdbc_xa_install instead of DLL/script installation.

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