[magnusp]

Closes #34. Part of #54.

What changed

• LibsqlResultSet.getObject(int, Class) now gates Integer, Long, Float, and Double on the current value's SQLite storage class, matching xerial 3.53.4.0 JDBC4ResultSet.getObject(int, Class) (JDBC4ResultSet.java:316-393). Only INTEGER and FLOAT storage convert; TEXT, BLOB, and NULL throw SQLException("Bad value for type <T>").
• Removed the Short and Byte branches. They now throw SQLFeatureNotSupportedException("not implemented by SQLite JDBC driver"), as do all other unsupported target types.
• Null target types now use xerial's message, requested type cannot be null.
• Documented the target-type by storage-class matrix in the method Javadoc.
• Added LibsqlResultSetGetObjectTest covering INTEGER, FLOAT, numeric text, non-numeric text, blobs, NULL, Short, Byte, unsupported target types, and the null target type. Updated the old test that expected numeric text to convert through getObject.

Contract decision

The xerial 3.53.4.0 gate wins, per #54's drop-in parity rule. Numeric wrapper targets convert only from INTEGER or FLOAT storage. This is a visible API reduction: Short and Byte were supported by this driver and are now rejected, and numeric text no longer converts to a numeric target through getObject(Class) (the plain numeric getters retain their SQLite coercion behavior). String, Boolean, BigDecimal, byte[], and the date/time targets keep their existing unrestricted conversions.

Evidence

Failing before the fix (new tests against the old implementation):

mise exec -- ./mvnw -pl libsql-jdbc -am -Dtest=LibsqlResultSetGetObjectTest -Dsurefire.failIfNoSpecifiedTests=false test
[ERROR] Tests run: 19, Failures: 11, Errors: 0, Skipped: 0
[ERROR] LibsqlResultSetGetObjectTest.numericTargetsRejectTextBlobAndNullStorage:72
Expecting code to raise a throwable.
[ERROR] LibsqlResultSetGetObjectTest.shortAndByteAreUnsupportedForEveryStorageClass:94
Expecting code to raise a throwable.
[ERROR] LibsqlResultSetGetObjectTest.unsupportedTargetTypeUsesXerialMessage:124
Expecting code to raise a throwable.
[ERROR] LibsqlResultSetGetObjectTest.unsupportedTargetTypeUsesXerialMessage:125
Expecting actual throwable to be exactly an instance of:
  java.sql.SQLFeatureNotSupportedException
but was:
  java.sql.SQLException: Cannot convert value of type class java.lang.Integer to java.util.UUID

Passing after the fix:

mise exec -- ./mvnw -pl libsql-jdbc -am -Dtest=LibsqlResultSetGetObjectTest,LibsqlResultSetTest -Dsurefire.failIfNoSpecifiedTests=false test
Tests run: 37, Failures: 0, Errors: 0, Skipped: 0
BUILD SUCCESS

mise exec -- ./mvnw -pl libsql-jdbc -am test
Tests run: 116, Failures: 0, Errors: 0, Skipped: 0
BUILD SUCCESS

mise exec -- ./mvnw -pl libsql-conformance -am verify
Tests run: 117, Failures: 0, Errors: 0, Skipped: 1
BUILD SUCCESS

mise exec -- ./mvnw spotless:apply
BUILD SUCCESS (no files changed)

The conformance run includes the vendored xerial ResultSetTest against live sqld, including getObjectWithRequestedType.

Deviations

None. The Short/Byte removal and rejection of numeric text are xerial parity, not transport-driven deviations.