Updated documentation and added test for wrapped type

Author: chernser

CHANGELOG.md

@@ -35,6 +35,8 @@
 
 - **[client-v2, jdbc-v2]** Added support for ClickHouse `Geometry` type for ClickHouse `25.11+`, where `Geometry` changed from a `String` alias to `Variant(Point, Ring, LineString, MultiLineString, Polygon, MultiPolygon)` (client still compatible with older versions). Includes client read/write handling and JDBC type mapping for retrieving and inserting geometry values. Current writes infer the target geometry variant from array nesting depth, so `Ring` vs `LineString` and `Polygon` vs `MultiLineString` are not yet distinguishable through the generic `Geometry` write path. (https://github.com/ClickHouse/clickhouse-java/pull/2815)
 
+- **[jdbc-v2]** `ResultSet#getObject(int|String, Map<String, Class<?>>)` now accepts ClickHouse type names as map keys in addition to the JDBC `SQLType` names it has always accepted. Only unwrapped type names are used for the lookup — `Nullable(...)` and `LowCardinality(...)` wrappers are stripped and do not affect resolution, so a key like `"Int32"` matches both `Int32` and `Nullable(Int32)` columns; keys like `"Nullable(Int32)"` are not recognized. Lookup order is the `ClickHouseDataType` enum name (e.g. `"Int32"`, `"String"`, `"DateTime"`) then the JDBC `SQLType` name (e.g. `"INTEGER"`, `"VARCHAR"`, `"TIMESTAMP"`); a missing entry leaves the value uncoerced. The feature is supported for primitive ClickHouse types only — `Array`, `Tuple`, `Map`, `Nested`, and geometry types are not supported and continue to be returned in their native form regardless of the user-supplied map. Existing maps keyed only by JDBC `SQLType` names continue to work unchanged.
+
 ### Bug Fixes
 
 - **[client-v2]** Fixed inconsistent use of `executionTimeout` parameter in `Client` component. The timeout was previously set in milliseconds but mistakenly retrieved and used in seconds in some places. Now it correctly uses milliseconds consistently. (https://github.com/ClickHouse/clickhouse-java/issues/2358)

docs/features.md

@@ -64,6 +64,7 @@ Compatibility-sensitive traits:
 - Database metadata: Implements JDBC `DatabaseMetaData` for ClickHouse catalogs, schemas, tables, columns, and related capability reporting.
 - Parameter metadata: Reports prepared-statement parameter counts.
 - Type mapping and conversions: Maps ClickHouse types to JDBC types and Java classes, including date/time handling and `java.time` support.
+- Custom result-set type map: `ResultSet#getObject(int|String, Map<String, Class<?>>)` accepts both ClickHouse type names and JDBC `SQLType` names as map keys. Only unwrapped type names are used — `Nullable(...)` and `LowCardinality(...)` wrappers are stripped before lookup, so a key like `"Int32"` matches both `Int32` and `Nullable(Int32)` columns, and keys like `"Nullable(Int32)"` are not recognized. Lookup order is `ClickHouseColumn#getDataType().name()` (e.g. `"Int32"`, `"String"`, `"DateTime"`) then `SQLType.getName()` (e.g. `"INTEGER"`, `"VARCHAR"`, `"TIMESTAMP"`); a missing entry leaves the value uncoerced (read as-is). The feature is supported for primitive ClickHouse types only — `Array`, `Tuple`, `Map`, `Nested`, and geometry types (`Point`, `Ring`, `LineString`, `Polygon`, `MultiPolygon`, `MultiLineString`, `Geometry`) bypass the type map and are returned in their native form.
 - Arrays and tuples: Supports JDBC arrays plus ClickHouse tuple values through custom `Array` and `Struct` implementations.
 - Geometry type mapping: For ClickHouse `25.11+`, where `Geometry` changed from a string alias to `Variant(Point, Ring, LineString, MultiLineString, Polygon, MultiPolygon)`, JDBC exposes `Geometry` as `ARRAY`, returns nested Java arrays from `getObject()`/`getArray()`, and accepts `Struct` or nested `Array` inputs for prepared-statement inserts depending on the geometry shape.
 - Client info propagation: Supports JDBC client info such as `ApplicationName` and forwards it to the underlying client name.

jdbc-v2/src/test/java/com/clickhouse/jdbc/ResultSetImplTest.java

@@ -524,6 +524,20 @@ public void testGetObjectWithClickHouseTypeNameMap() throws SQLException {
         }
     }
 
+    @Test(groups = {"integration"})
+    public void testGetObjectCustomMappingWithWrappedTypes() throws SQLException {
+        try (Connection conn = getJdbcConnection(); Statement stmt = conn.createStatement();
+             ResultSet rs = stmt.executeQuery(
+                     "SELECT CAST(32 AS Nullable(Int32)) AS n")) {
+            assertTrue(rs.next());
+
+            Map<String, Class<?>> typeMap = new HashMap<>();
+            typeMap.put("Int32", Long.class);
+            Object n = rs.getObject("n", typeMap);
+            assertEquals(n, 32L, "Value was of " + n.getClass().getName() + " but should be Long");
+        }
+    }
+
     @Test(groups = {"integration"})
     public void testGetObjectWithMixedTypeNameMap() throws SQLException {
         // Single typeMap mixing ClickHouseDataType names and SQLType names: CH-name lookup is tried