Specify flexible generics nullness in spring-jdbc

This commit leverages flexible generics nullness at method and
type level when relevant in spring-jdbc.

Due to https://github.com/uber/NullAway/issues/1075, some related
`@SuppressWarnings("NullAway")` have been added.

JdbcOperations Kotlin extensions have been refined accordingly.

Closes gh-34911

spring-core/src/main/java/org/springframework/util/CollectionUtils.java

@@ -110,7 +110,7 @@ public abstract class CollectionUtils {
 	 * @since 5.3
 	 * @see #newHashMap(int)
 	 */
-	public static <K, V> LinkedHashMap<K, V> newLinkedHashMap(int expectedSize) {
+	public static <K, V extends @Nullable Object> LinkedHashMap<K, V> newLinkedHashMap(int expectedSize) {
 		return new LinkedHashMap<>(computeInitialCapacity(expectedSize), DEFAULT_LOAD_FACTOR);
 	}
 

spring-jdbc/src/main/java/org/springframework/jdbc/core/CallableStatementCallback.java

@@ -44,7 +44,7 @@ import org.springframework.dao.DataAccessException;
  * @see JdbcTemplate#execute(CallableStatementCreator, CallableStatementCallback)
  */
 @FunctionalInterface
-public interface CallableStatementCallback<T> {
+public interface CallableStatementCallback<T extends @Nullable Object> {
 
 	/**
 	 * Gets called by {@code JdbcTemplate.execute} with an active JDBC
@@ -75,6 +75,6 @@ public interface CallableStatementCallback<T> {
 	 * into a DataAccessException by an SQLExceptionTranslator
 	 * @throws DataAccessException in case of custom exceptions
 	 */
-	@Nullable T doInCallableStatement(CallableStatement cs) throws SQLException, DataAccessException;
+	T doInCallableStatement(CallableStatement cs) throws SQLException, DataAccessException;
 
 }

spring-jdbc/src/main/java/org/springframework/jdbc/core/ColumnMapRowMapper.java

@@ -44,13 +44,13 @@ import org.springframework.util.LinkedCaseInsensitiveMap;
  * @see JdbcTemplate#queryForList(String)
  * @see JdbcTemplate#queryForMap(String)
  */
-public class ColumnMapRowMapper implements RowMapper<Map<String, Object>> {
+public class ColumnMapRowMapper implements RowMapper<Map<String, @Nullable Object>> {
 
 	@Override
-	public Map<String, Object> mapRow(ResultSet rs, int rowNum) throws SQLException {
+	public Map<String, @Nullable Object> mapRow(ResultSet rs, int rowNum) throws SQLException {
 		ResultSetMetaData rsmd = rs.getMetaData();
 		int columnCount = rsmd.getColumnCount();
-		Map<String, Object> mapOfColumnValues = createColumnMap(columnCount);
+		Map<String, @Nullable Object> mapOfColumnValues = createColumnMap(columnCount);
 		for (int i = 1; i <= columnCount; i++) {
 			String column = JdbcUtils.lookupColumnName(rsmd, i);
 			mapOfColumnValues.putIfAbsent(getColumnKey(column), getColumnValue(rs, i));
@@ -66,7 +66,7 @@ public class ColumnMapRowMapper implements RowMapper<Map<String, Object>> {
 	 * @return the new Map instance
 	 * @see org.springframework.util.LinkedCaseInsensitiveMap
 	 */
-	protected Map<String, Object> createColumnMap(int columnCount) {
+	protected Map<String, @Nullable Object> createColumnMap(int columnCount) {
 		return new LinkedCaseInsensitiveMap<>(columnCount);
 	}
 

spring-jdbc/src/main/java/org/springframework/jdbc/core/ConnectionCallback.java

@@ -41,7 +41,7 @@ import org.springframework.dao.DataAccessException;
  * @see JdbcTemplate#update
  */
 @FunctionalInterface
-public interface ConnectionCallback<T> {
+public interface ConnectionCallback<T extends @Nullable Object> {
 
 	/**
 	 * Gets called by {@code JdbcTemplate.execute} with an active JDBC
@@ -65,6 +65,6 @@ public interface ConnectionCallback<T> {
 	 * @see JdbcTemplate#queryForObject(String, Class)
 	 * @see JdbcTemplate#queryForRowSet(String)
 	 */
-	@Nullable T doInConnection(Connection con) throws SQLException, DataAccessException;
+	T doInConnection(Connection con) throws SQLException, DataAccessException;
 
 }

spring-jdbc/src/main/java/org/springframework/jdbc/core/JdbcOperations.java

@@ -68,7 +68,7 @@ public interface JdbcOperations {
 	 * @return a result object returned by the action, or {@code null} if none
 	 * @throws DataAccessException if there is any problem
 	 */
-	<T> @Nullable T execute(ConnectionCallback<T> action) throws DataAccessException;
+	<T extends @Nullable Object> T execute(ConnectionCallback<T> action) throws DataAccessException;
 
 
 	//-------------------------------------------------------------------------
@@ -87,7 +87,7 @@ public interface JdbcOperations {
 	 * @return a result object returned by the action, or {@code null} if none
 	 * @throws DataAccessException if there is any problem
 	 */
-	<T> @Nullable T execute(StatementCallback<T> action) throws DataAccessException;
+	<T extends @Nullable Object> T execute(StatementCallback<T> action) throws DataAccessException;
 
 	/**
 	 * Issue a single SQL execute, typically a DDL statement.
@@ -108,7 +108,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if there is any problem executing the query
 	 * @see #query(String, ResultSetExtractor, Object...)
 	 */
-	<T> @Nullable T query(String sql, ResultSetExtractor<T> rse) throws DataAccessException;
+	<T extends @Nullable Object> T query(String sql, ResultSetExtractor<T> rse) throws DataAccessException;
 
 	/**
 	 * Execute a query given static SQL, reading the ResultSet on a per-row
@@ -135,7 +135,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if there is any problem executing the query
 	 * @see #query(String, RowMapper, Object...)
 	 */
-	<T> List<T> query(String sql, RowMapper<T> rowMapper) throws DataAccessException;
+	<T extends @Nullable Object> List<T> query(String sql, RowMapper<T> rowMapper) throws DataAccessException;
 
 	/**
 	 * Execute a query given static SQL, mapping each row to a result object
@@ -151,7 +151,7 @@ public interface JdbcOperations {
 	 * @since 5.3
 	 * @see #queryForStream(String, RowMapper, Object...)
 	 */
-	<T> Stream<T> queryForStream(String sql, RowMapper<T> rowMapper) throws DataAccessException;
+	<T extends @Nullable Object> Stream<T> queryForStream(String sql, RowMapper<T> rowMapper) throws DataAccessException;
 
 	/**
 	 * Execute a query given static SQL, mapping a single result row to a
@@ -169,7 +169,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if there is any problem executing the query
 	 * @see #queryForObject(String, RowMapper, Object...)
 	 */
-	<T> @Nullable T queryForObject(String sql, RowMapper<T> rowMapper) throws DataAccessException;
+	<T extends @Nullable Object> T queryForObject(String sql, RowMapper<T> rowMapper) throws DataAccessException;
 
 	/**
 	 * Execute a query for a result object, given static SQL.
@@ -208,7 +208,7 @@ public interface JdbcOperations {
 	 * @see #queryForMap(String, Object...)
 	 * @see ColumnMapRowMapper
 	 */
-	Map<String, Object> queryForMap(String sql) throws DataAccessException;
+	Map<String, @Nullable Object> queryForMap(String sql) throws DataAccessException;
 
 	/**
 	 * Execute a query for a result list, given static SQL.
@@ -225,7 +225,7 @@ public interface JdbcOperations {
 	 * @see #queryForList(String, Class, Object...)
 	 * @see SingleColumnRowMapper
 	 */
-	<T> List<T> queryForList(String sql, Class<T> elementType) throws DataAccessException;
+	<T> List<@Nullable T> queryForList(String sql, Class<T> elementType) throws DataAccessException;
 
 	/**
 	 * Execute a query for a result list, given static SQL.
@@ -241,7 +241,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if there is any problem executing the query
 	 * @see #queryForList(String, Object...)
 	 */
-	List<Map<String, Object>> queryForList(String sql) throws DataAccessException;
+	List<Map<String, @Nullable Object>> queryForList(String sql) throws DataAccessException;
 
 	/**
 	 * Execute a query for an SqlRowSet, given static SQL.
@@ -299,7 +299,7 @@ public interface JdbcOperations {
 	 * @return a result object returned by the action, or {@code null} if none
 	 * @throws DataAccessException if there is any problem
 	 */
-	<T> @Nullable T execute(PreparedStatementCreator psc, PreparedStatementCallback<T> action) throws DataAccessException;
+	<T extends @Nullable Object> T execute(PreparedStatementCreator psc, PreparedStatementCallback<T> action) throws DataAccessException;
 
 	/**
 	 * Execute a JDBC data access operation, implemented as callback action
@@ -314,7 +314,7 @@ public interface JdbcOperations {
 	 * @return a result object returned by the action, or {@code null} if none
 	 * @throws DataAccessException if there is any problem
 	 */
-	<T> @Nullable T execute(String sql, PreparedStatementCallback<T> action) throws DataAccessException;
+	<T extends @Nullable Object> T execute(String sql, PreparedStatementCallback<T> action) throws DataAccessException;
 
 	/**
 	 * Query using a prepared statement, reading the ResultSet with a ResultSetExtractor.
@@ -326,7 +326,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if there is any problem
 	 * @see PreparedStatementCreatorFactory
 	 */
-	<T> @Nullable T query(PreparedStatementCreator psc, ResultSetExtractor<T> rse) throws DataAccessException;
+	<T extends @Nullable Object> T query(PreparedStatementCreator psc, ResultSetExtractor<T> rse) throws DataAccessException;
 
 	/**
 	 * Query using a prepared statement, reading the ResultSet with a ResultSetExtractor.
@@ -339,7 +339,7 @@ public interface JdbcOperations {
 	 * @return an arbitrary result object, as returned by the ResultSetExtractor
 	 * @throws DataAccessException if there is any problem
 	 */
-	<T> @Nullable T query(String sql, @Nullable PreparedStatementSetter pss, ResultSetExtractor<T> rse)
+	<T extends @Nullable Object> T query(String sql, @Nullable PreparedStatementSetter pss, ResultSetExtractor<T> rse)
 			throws DataAccessException;
 
 	/**
@@ -354,7 +354,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if the query fails
 	 * @see java.sql.Types
 	 */
-	<T> @Nullable T query(String sql, @Nullable Object @Nullable [] args, int[] argTypes, ResultSetExtractor<T> rse) throws DataAccessException;
+	<T extends @Nullable Object> T query(String sql, @Nullable Object @Nullable [] args, int[] argTypes, ResultSetExtractor<T> rse) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list of arguments
@@ -370,7 +370,7 @@ public interface JdbcOperations {
 	 * @deprecated in favor of {@link #query(String, ResultSetExtractor, Object...)}
 	 */
 	@Deprecated(since = "5.3")
-	<T> @Nullable T query(String sql, @Nullable Object @Nullable [] args, ResultSetExtractor<T> rse) throws DataAccessException;
+	<T extends @Nullable Object> T query(String sql, @Nullable Object @Nullable [] args, ResultSetExtractor<T> rse) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list of arguments
@@ -385,7 +385,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if the query fails
 	 * @since 3.0.1
 	 */
-	<T> @Nullable T query(String sql, ResultSetExtractor<T> rse, @Nullable Object @Nullable ... args) throws DataAccessException;
+	<T extends @Nullable Object> T query(String sql, ResultSetExtractor<T> rse, @Nullable Object @Nullable ... args) throws DataAccessException;
 
 	/**
 	 * Query using a prepared statement, reading the ResultSet on a per-row basis
@@ -469,7 +469,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if there is any problem
 	 * @see PreparedStatementCreatorFactory
 	 */
-	<T> List<T> query(PreparedStatementCreator psc, RowMapper<T> rowMapper) throws DataAccessException;
+	<T extends @Nullable Object> List<T> query(PreparedStatementCreator psc, RowMapper<T> rowMapper) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a
@@ -484,7 +484,7 @@ public interface JdbcOperations {
 	 * @return the result List, containing mapped objects
 	 * @throws DataAccessException if the query fails
 	 */
-	<T> List<T> query(String sql, @Nullable PreparedStatementSetter pss, RowMapper<T> rowMapper)
+	<T extends @Nullable Object> List<T> query(String sql, @Nullable PreparedStatementSetter pss, RowMapper<T> rowMapper)
 			throws DataAccessException;
 
 	/**
@@ -500,7 +500,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if the query fails
 	 * @see java.sql.Types
 	 */
-	<T> List<T> query(String sql, @Nullable Object @Nullable [] args, int[] argTypes, RowMapper<T> rowMapper) throws DataAccessException;
+	<T extends @Nullable Object> List<T> query(String sql, @Nullable Object @Nullable [] args, int[] argTypes, RowMapper<T> rowMapper) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list of
@@ -517,7 +517,7 @@ public interface JdbcOperations {
 	 * @deprecated in favor of {@link #query(String, RowMapper, Object...)}
 	 */
 	@Deprecated(since = "5.3")
-	<T> List<T> query(String sql, @Nullable Object @Nullable [] args, RowMapper<T> rowMapper) throws DataAccessException;
+	<T extends @Nullable Object> List<T> query(String sql, @Nullable Object @Nullable [] args, RowMapper<T> rowMapper) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list of
@@ -533,7 +533,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if the query fails
 	 * @since 3.0.1
 	 */
-	<T> List<T> query(String sql, RowMapper<T> rowMapper, @Nullable Object @Nullable ... args) throws DataAccessException;
+	<T extends @Nullable Object> List<T> query(String sql, RowMapper<T> rowMapper, @Nullable Object @Nullable ... args) throws DataAccessException;
 
 	/**
 	 * Query using a prepared statement, mapping each row to a result object
@@ -548,7 +548,7 @@ public interface JdbcOperations {
 	 * @see PreparedStatementCreatorFactory
 	 * @since 5.3
 	 */
-	<T> Stream<T> queryForStream(PreparedStatementCreator psc, RowMapper<T> rowMapper) throws DataAccessException;
+	<T extends @Nullable Object> Stream<T> queryForStream(PreparedStatementCreator psc, RowMapper<T> rowMapper) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a
@@ -566,7 +566,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if the query fails
 	 * @since 5.3
 	 */
-	<T> Stream<T> queryForStream(String sql, @Nullable PreparedStatementSetter pss, RowMapper<T> rowMapper)
+	<T extends @Nullable Object> Stream<T> queryForStream(String sql, @Nullable PreparedStatementSetter pss, RowMapper<T> rowMapper)
 			throws DataAccessException;
 
 	/**
@@ -584,7 +584,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if the query fails
 	 * @since 5.3
 	 */
-	<T> Stream<T> queryForStream(String sql, RowMapper<T> rowMapper, @Nullable Object @Nullable ... args)
+	<T extends @Nullable Object> Stream<T> queryForStream(String sql, RowMapper<T> rowMapper, @Nullable Object @Nullable ... args)
 			throws DataAccessException;
 
 	/**
@@ -603,7 +603,7 @@ public interface JdbcOperations {
 	 * if the query does not return exactly one row
 	 * @throws DataAccessException if the query fails
 	 */
-	<T> @Nullable T queryForObject(String sql, @Nullable Object @Nullable [] args, int[] argTypes, RowMapper<T> rowMapper)
+	<T extends @Nullable Object> T queryForObject(String sql, @Nullable Object @Nullable [] args, int[] argTypes, RowMapper<T> rowMapper)
 			throws DataAccessException;
 
 	/**
@@ -624,7 +624,7 @@ public interface JdbcOperations {
 	 * @deprecated in favor of {@link #queryForObject(String, RowMapper, Object...)}
 	 */
 	@Deprecated(since = "5.3")
-	<T> @Nullable T queryForObject(String sql, @Nullable Object @Nullable [] args, RowMapper<T> rowMapper) throws DataAccessException;
+	<T extends @Nullable Object> T queryForObject(String sql, @Nullable Object @Nullable [] args, RowMapper<T> rowMapper) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list
@@ -643,7 +643,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if the query fails
 	 * @since 3.0.1
 	 */
-	<T> @Nullable T queryForObject(String sql, RowMapper<T> rowMapper, @Nullable Object @Nullable ... args) throws DataAccessException;
+	<T extends @Nullable Object> T queryForObject(String sql, RowMapper<T> rowMapper, @Nullable Object @Nullable ... args) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list of
@@ -729,7 +729,7 @@ public interface JdbcOperations {
 	 * @see ColumnMapRowMapper
 	 * @see java.sql.Types
 	 */
-	Map<String, Object> queryForMap(String sql, @Nullable Object @Nullable [] args, int[] argTypes) throws DataAccessException;
+	Map<String, @Nullable Object> queryForMap(String sql, @Nullable Object @Nullable [] args, int[] argTypes) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list of
@@ -752,7 +752,7 @@ public interface JdbcOperations {
 	 * @see #queryForMap(String)
 	 * @see ColumnMapRowMapper
 	 */
-	Map<String, Object> queryForMap(String sql, @Nullable Object @Nullable ... args) throws DataAccessException;
+	Map<String, @Nullable Object> queryForMap(String sql, @Nullable Object @Nullable ... args) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list of
@@ -770,7 +770,7 @@ public interface JdbcOperations {
 	 * @see #queryForList(String, Class)
 	 * @see SingleColumnRowMapper
 	 */
-	<T> List<T> queryForList(String sql, @Nullable Object @Nullable [] args, int[] argTypes, Class<T> elementType)
+	<T> List<@Nullable T> queryForList(String sql, @Nullable Object @Nullable [] args, int[] argTypes, Class<T> elementType)
 			throws DataAccessException;
 
 	/**
@@ -792,7 +792,7 @@ public interface JdbcOperations {
 	 * @deprecated in favor of {@link #queryForList(String, Class, Object...)}
 	 */
 	@Deprecated(since = "5.3")
-	<T> List<T> queryForList(String sql, @Nullable Object @Nullable [] args, Class<T> elementType) throws DataAccessException;
+	<T> List<@Nullable T> queryForList(String sql, @Nullable Object @Nullable [] args, Class<T> elementType) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list of
@@ -812,7 +812,7 @@ public interface JdbcOperations {
 	 * @see #queryForList(String, Class)
 	 * @see SingleColumnRowMapper
 	 */
-	<T> List<T> queryForList(String sql, Class<T> elementType, @Nullable Object @Nullable ... args) throws DataAccessException;
+	<T> List<@Nullable T> queryForList(String sql, Class<T> elementType, @Nullable Object @Nullable ... args) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list of
@@ -830,7 +830,7 @@ public interface JdbcOperations {
 	 * @see #queryForList(String)
 	 * @see java.sql.Types
 	 */
-	List<Map<String, Object>> queryForList(String sql, @Nullable Object @Nullable [] args, int[] argTypes) throws DataAccessException;
+	List<Map<String, @Nullable Object>> queryForList(String sql, @Nullable Object @Nullable [] args, int[] argTypes) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list of
@@ -848,7 +848,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if the query fails
 	 * @see #queryForList(String)
 	 */
-	List<Map<String, Object>> queryForList(String sql, @Nullable Object @Nullable ... args) throws DataAccessException;
+	List<Map<String, @Nullable Object>> queryForList(String sql, @Nullable Object @Nullable ... args) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list of
@@ -1064,7 +1064,7 @@ public interface JdbcOperations {
 	 * @return a result object returned by the action, or {@code null} if none
 	 * @throws DataAccessException if there is any problem
 	 */
-	<T> @Nullable T execute(CallableStatementCreator csc, CallableStatementCallback<T> action) throws DataAccessException;
+	<T extends @Nullable Object> T execute(CallableStatementCreator csc, CallableStatementCallback<T> action) throws DataAccessException;
 
 	/**
 	 * Execute a JDBC data access operation, implemented as callback action
@@ -1079,7 +1079,7 @@ public interface JdbcOperations {
 	 * @return a result object returned by the action, or {@code null} if none
 	 * @throws DataAccessException if there is any problem
 	 */
-	<T> @Nullable T execute(String callString, CallableStatementCallback<T> action) throws DataAccessException;
+	<T extends @Nullable Object> T execute(String callString, CallableStatementCallback<T> action) throws DataAccessException;
 
 	/**
 	 * Execute an SQL call using a CallableStatementCreator to provide SQL and
@@ -1089,7 +1089,7 @@ public interface JdbcOperations {
 	 * @return a Map of extracted out parameters
 	 * @throws DataAccessException if there is any problem issuing the update
 	 */
-	Map<String, Object> call(CallableStatementCreator csc, List<SqlParameter> declaredParameters)
+	Map<String, @Nullable Object> call(CallableStatementCreator csc, List<SqlParameter> declaredParameters)
 			throws DataAccessException;
 
 }

spring-jdbc/src/main/java/org/springframework/jdbc/core/JdbcTemplate.java

@@ -357,7 +357,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	//-------------------------------------------------------------------------
 
 	@Override
-	public <T> @Nullable T execute(ConnectionCallback<T> action) throws DataAccessException {
+	public <T extends @Nullable Object> T execute(ConnectionCallback<T> action) throws DataAccessException {
 		Assert.notNull(action, "Callback object must not be null");
 
 		Connection con = DataSourceUtils.getConnection(obtainDataSource());
@@ -402,7 +402,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	// Methods dealing with static SQL (java.sql.Statement)
 	//-------------------------------------------------------------------------
 
-	private <T> @Nullable T execute(StatementCallback<T> action, boolean closeResources) throws DataAccessException {
+	private <T extends @Nullable Object> T execute(StatementCallback<T> action, boolean closeResources) throws DataAccessException {
 		Assert.notNull(action, "Callback object must not be null");
 
 		Connection con = DataSourceUtils.getConnection(obtainDataSource());
@@ -436,18 +436,19 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
-	public <T> @Nullable T execute(StatementCallback<T> action) throws DataAccessException {
+	public <T extends @Nullable Object> T execute(StatementCallback<T> action) throws DataAccessException {
 		return execute(action, true);
 	}
 
 	@Override
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
 	public void execute(String sql) throws DataAccessException {
 		if (logger.isDebugEnabled()) {
 			logger.debug("Executing SQL statement [" + sql + "]");
 		}
 
 		// Callback to execute the statement.
-		class ExecuteStatementCallback implements StatementCallback<Object>, SqlProvider {
+		class ExecuteStatementCallback implements StatementCallback<@Nullable Object>, SqlProvider {
 			@Override
 			public @Nullable Object doInStatement(Statement stmt) throws SQLException {
 				stmt.execute(sql);
@@ -463,7 +464,8 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
-	public <T> @Nullable T query(String sql, ResultSetExtractor<T> rse) throws DataAccessException {
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
+	public <T extends @Nullable Object> T query(String sql, ResultSetExtractor<T> rse) throws DataAccessException {
 		Assert.notNull(sql, "SQL must not be null");
 		Assert.notNull(rse, "ResultSetExtractor must not be null");
 		if (logger.isDebugEnabled()) {
@@ -493,12 +495,13 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
 	public void query(String sql, RowCallbackHandler rch) throws DataAccessException {
 		query(sql, new RowCallbackHandlerResultSetExtractor(rch, this.maxRows));
 	}
 
 	@Override
-	public <T> List<T> query(String sql, RowMapper<T> rowMapper) throws DataAccessException {
+	public <T extends @Nullable Object> List<T> query(String sql, RowMapper<T> rowMapper) throws DataAccessException {
 		return result(query(sql, new RowMapperResultSetExtractor<>(rowMapper, 0, this.maxRows)));
 	}
 
@@ -525,12 +528,12 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
-	public Map<String, Object> queryForMap(String sql) throws DataAccessException {
+	public Map<String, @Nullable Object> queryForMap(String sql) throws DataAccessException {
 		return result(queryForObject(sql, getColumnMapRowMapper()));
 	}
 
 	@Override
-	public <T> @Nullable T queryForObject(String sql, RowMapper<T> rowMapper) throws DataAccessException {
+	public <T extends @Nullable Object> T queryForObject(String sql, RowMapper<T> rowMapper) throws DataAccessException {
 		List<T> results = query(sql, rowMapper);
 		return DataAccessUtils.nullableSingleResult(results);
 	}
@@ -541,12 +544,13 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
-	public <T> List<T> queryForList(String sql, Class<T> elementType) throws DataAccessException {
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
+	public <T> List<@Nullable T> queryForList(String sql, Class<T> elementType) throws DataAccessException {
 		return query(sql, getSingleColumnRowMapper(elementType));
 	}
 
 	@Override
-	public List<Map<String, Object>> queryForList(String sql) throws DataAccessException {
+	public List<Map<String, @Nullable Object>> queryForList(String sql) throws DataAccessException {
 		return query(sql, getColumnMapRowMapper());
 	}
 
@@ -651,7 +655,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	// Methods dealing with prepared statements
 	//-------------------------------------------------------------------------
 
-	private <T> @Nullable T execute(PreparedStatementCreator psc, PreparedStatementCallback<T> action, boolean closeResources)
+	private <T extends @Nullable Object> T execute(PreparedStatementCreator psc, PreparedStatementCallback<T> action, boolean closeResources)
 			throws DataAccessException {
 
 		Assert.notNull(psc, "PreparedStatementCreator must not be null");
@@ -699,14 +703,14 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
-	public <T> @Nullable T execute(PreparedStatementCreator psc, PreparedStatementCallback<T> action)
+	public <T extends @Nullable Object> T execute(PreparedStatementCreator psc, PreparedStatementCallback<T> action)
 			throws DataAccessException {
 
 		return execute(psc, action, true);
 	}
 
 	@Override
-	public <T> @Nullable T execute(String sql, PreparedStatementCallback<T> action) throws DataAccessException {
+	public <T extends @Nullable Object> T execute(String sql, PreparedStatementCallback<T> action) throws DataAccessException {
 		return execute(new SimplePreparedStatementCreator(sql), action, true);
 	}
 
@@ -747,37 +751,41 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
-	public <T> @Nullable T query(PreparedStatementCreator psc, ResultSetExtractor<T> rse) throws DataAccessException {
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
+	public <T extends @Nullable Object> T query(PreparedStatementCreator psc, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(psc, null, rse);
 	}
 
 	@Override
-	public <T> @Nullable T query(String sql, @Nullable PreparedStatementSetter pss, ResultSetExtractor<T> rse) throws DataAccessException {
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
+	public <T extends @Nullable Object> T query(String sql, @Nullable PreparedStatementSetter pss, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(new SimplePreparedStatementCreator(sql), pss, rse);
 	}
 
 	@Override
-	public <T> @Nullable T query(String sql, @Nullable Object @Nullable [] args, int[] argTypes, ResultSetExtractor<T> rse) throws DataAccessException {
+	public <T extends @Nullable Object> T query(String sql, @Nullable Object @Nullable [] args, int[] argTypes, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(sql, newArgTypePreparedStatementSetter(args, argTypes), rse);
 	}
 
 	@Deprecated(since = "5.3")
 	@Override
-	public <T> @Nullable T query(String sql, @Nullable Object @Nullable [] args, ResultSetExtractor<T> rse) throws DataAccessException {
+	public <T extends @Nullable Object> T query(String sql, @Nullable Object @Nullable [] args, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(sql, newArgPreparedStatementSetter(args), rse);
 	}
 
 	@Override
-	public <T> @Nullable T query(String sql, ResultSetExtractor<T> rse, @Nullable Object @Nullable ... args) throws DataAccessException {
+	public <T extends @Nullable Object> T query(String sql, ResultSetExtractor<T> rse, @Nullable Object @Nullable ... args) throws DataAccessException {
 		return query(sql, newArgPreparedStatementSetter(args), rse);
 	}
 
 	@Override
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
 	public void query(PreparedStatementCreator psc, RowCallbackHandler rch) throws DataAccessException {
 		query(psc, new RowCallbackHandlerResultSetExtractor(rch, this.maxRows));
 	}
 
 	@Override
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
 	public void query(String sql, @Nullable PreparedStatementSetter pss, RowCallbackHandler rch) throws DataAccessException {
 		query(sql, pss, new RowCallbackHandlerResultSetExtractor(rch, this.maxRows));
 	}
@@ -799,28 +807,28 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
-	public <T> List<T> query(PreparedStatementCreator psc, RowMapper<T> rowMapper) throws DataAccessException {
+	public <T extends @Nullable Object> List<T> query(PreparedStatementCreator psc, RowMapper<T> rowMapper) throws DataAccessException {
 		return result(query(psc, new RowMapperResultSetExtractor<>(rowMapper, 0, this.maxRows)));
 	}
 
 	@Override
-	public <T> List<T> query(String sql, @Nullable PreparedStatementSetter pss, RowMapper<T> rowMapper) throws DataAccessException {
+	public <T extends @Nullable Object> List<T> query(String sql, @Nullable PreparedStatementSetter pss, RowMapper<T> rowMapper) throws DataAccessException {
 		return result(query(sql, pss, new RowMapperResultSetExtractor<>(rowMapper, 0, this.maxRows)));
 	}
 
 	@Override
-	public <T> List<T> query(String sql, @Nullable Object @Nullable [] args, int[] argTypes, RowMapper<T> rowMapper) throws DataAccessException {
+	public <T extends @Nullable Object> List<T> query(String sql, @Nullable Object @Nullable [] args, int[] argTypes, RowMapper<T> rowMapper) throws DataAccessException {
 		return result(query(sql, args, argTypes, new RowMapperResultSetExtractor<>(rowMapper, 0, this.maxRows)));
 	}
 
 	@Deprecated(since = "5.3")
 	@Override
-	public <T> List<T> query(String sql, @Nullable Object @Nullable [] args, RowMapper<T> rowMapper) throws DataAccessException {
+	public <T extends @Nullable Object> List<T> query(String sql, @Nullable Object @Nullable [] args, RowMapper<T> rowMapper) throws DataAccessException {
 		return result(query(sql, newArgPreparedStatementSetter(args), new RowMapperResultSetExtractor<>(rowMapper, 0, this.maxRows)));
 	}
 
 	@Override
-	public <T> List<T> query(String sql, RowMapper<T> rowMapper, @Nullable Object @Nullable ... args) throws DataAccessException {
+	public <T extends @Nullable Object> List<T> query(String sql, RowMapper<T> rowMapper, @Nullable Object @Nullable ... args) throws DataAccessException {
 		return result(query(sql, newArgPreparedStatementSetter(args), new RowMapperResultSetExtractor<>(rowMapper, 0, this.maxRows)));
 	}
 
@@ -837,7 +845,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	 * @throws DataAccessException if the query fails
 	 * @since 5.3
 	 */
-	public <T> Stream<T> queryForStream(PreparedStatementCreator psc, @Nullable PreparedStatementSetter pss,
+	public <T extends @Nullable Object> Stream<T> queryForStream(PreparedStatementCreator psc, @Nullable PreparedStatementSetter pss,
 			RowMapper<T> rowMapper) throws DataAccessException {
 
 		return result(execute(psc, ps -> {
@@ -858,22 +866,22 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
-	public <T> Stream<T> queryForStream(PreparedStatementCreator psc, RowMapper<T> rowMapper) throws DataAccessException {
+	public <T extends @Nullable Object> Stream<T> queryForStream(PreparedStatementCreator psc, RowMapper<T> rowMapper) throws DataAccessException {
 		return queryForStream(psc, null, rowMapper);
 	}
 
 	@Override
-	public <T> Stream<T> queryForStream(String sql, @Nullable PreparedStatementSetter pss, RowMapper<T> rowMapper) throws DataAccessException {
+	public <T extends @Nullable Object> Stream<T> queryForStream(String sql, @Nullable PreparedStatementSetter pss, RowMapper<T> rowMapper) throws DataAccessException {
 		return queryForStream(new SimplePreparedStatementCreator(sql), pss, rowMapper);
 	}
 
 	@Override
-	public <T> Stream<T> queryForStream(String sql, RowMapper<T> rowMapper, @Nullable Object @Nullable ... args) throws DataAccessException {
+	public <T extends @Nullable Object> Stream<T> queryForStream(String sql, RowMapper<T> rowMapper, @Nullable Object @Nullable ... args) throws DataAccessException {
 		return queryForStream(new SimplePreparedStatementCreator(sql), newArgPreparedStatementSetter(args), rowMapper);
 	}
 
 	@Override
-	public <T> @Nullable T queryForObject(String sql, @Nullable Object @Nullable [] args, int[] argTypes, RowMapper<T> rowMapper)
+	public <T extends @Nullable Object> T queryForObject(String sql, @Nullable Object @Nullable [] args, int[] argTypes, RowMapper<T> rowMapper)
 			throws DataAccessException {
 
 		List<T> results = query(sql, args, argTypes, new RowMapperResultSetExtractor<>(rowMapper, 1));
@@ -882,13 +890,13 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 
 	@Deprecated(since = "5.3")
 	@Override
-	public <T> @Nullable T queryForObject(String sql,@Nullable Object @Nullable [] args, RowMapper<T> rowMapper) throws DataAccessException {
+	public <T extends @Nullable Object> T queryForObject(String sql, @Nullable Object @Nullable [] args, RowMapper<T> rowMapper) throws DataAccessException {
 		List<T> results = query(sql, newArgPreparedStatementSetter(args), new RowMapperResultSetExtractor<>(rowMapper, 1));
 		return DataAccessUtils.nullableSingleResult(results);
 	}
 
 	@Override
-	public <T> @Nullable T queryForObject(String sql, RowMapper<T> rowMapper, @Nullable Object @Nullable ... args) throws DataAccessException {
+	public <T extends @Nullable Object> T queryForObject(String sql, RowMapper<T> rowMapper, @Nullable Object @Nullable ... args) throws DataAccessException {
 		List<T> results = query(sql, newArgPreparedStatementSetter(args), new RowMapperResultSetExtractor<>(rowMapper, 1));
 		return DataAccessUtils.nullableSingleResult(results);
 	}
@@ -912,38 +920,41 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
-	public Map<String, Object> queryForMap(String sql, @Nullable Object @Nullable [] args, int[] argTypes) throws DataAccessException {
+	public Map<String, @Nullable Object> queryForMap(String sql, @Nullable Object @Nullable [] args, int[] argTypes) throws DataAccessException {
 		return result(queryForObject(sql, args, argTypes, getColumnMapRowMapper()));
 	}
 
 	@Override
-	public Map<String, Object> queryForMap(String sql, @Nullable Object @Nullable ... args) throws DataAccessException {
+	public Map<String, @Nullable Object> queryForMap(String sql, @Nullable Object @Nullable ... args) throws DataAccessException {
 		return result(queryForObject(sql, getColumnMapRowMapper(), args));
 	}
 
 	@Override
-	public <T> List<T> queryForList(String sql, @Nullable Object @Nullable [] args, int[] argTypes, Class<T> elementType) throws DataAccessException {
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
+	public <T> List<@Nullable T> queryForList(String sql, @Nullable Object @Nullable [] args, int[] argTypes, Class<T> elementType) throws DataAccessException {
 		return query(sql, args, argTypes, getSingleColumnRowMapper(elementType));
 	}
 
 	@Deprecated(since = "5.3")
 	@Override
-	public <T> List<T> queryForList(String sql, @Nullable Object @Nullable [] args, Class<T> elementType) throws DataAccessException {
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
+	public <T> List<@Nullable T> queryForList(String sql, @Nullable Object @Nullable [] args, Class<T> elementType) throws DataAccessException {
 		return query(sql, newArgPreparedStatementSetter(args), getSingleColumnRowMapper(elementType));
 	}
 
 	@Override
-	public <T> List<T> queryForList(String sql, Class<T> elementType, @Nullable Object @Nullable ... args) throws DataAccessException {
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
+	public <T> List<@Nullable T> queryForList(String sql, Class<T> elementType, @Nullable Object @Nullable ... args) throws DataAccessException {
 		return query(sql, newArgPreparedStatementSetter(args), getSingleColumnRowMapper(elementType));
 	}
 
 	@Override
-	public List<Map<String, Object>> queryForList(String sql, @Nullable Object @Nullable [] args, int[] argTypes) throws DataAccessException {
+	public List<Map<String, @Nullable Object>> queryForList(String sql, @Nullable Object @Nullable [] args, int[] argTypes) throws DataAccessException {
 		return query(sql, args, argTypes, getColumnMapRowMapper());
 	}
 
 	@Override
-	public List<Map<String, Object>> queryForList(String sql, @Nullable Object @Nullable ... args) throws DataAccessException {
+	public List<Map<String, @Nullable Object>> queryForList(String sql, @Nullable Object @Nullable ... args) throws DataAccessException {
 		return query(sql, newArgPreparedStatementSetter(args), getColumnMapRowMapper());
 	}
 
@@ -1146,7 +1157,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	//-------------------------------------------------------------------------
 
 	@Override
-	public <T> @Nullable T execute(CallableStatementCreator csc, CallableStatementCallback<T> action)
+	public <T extends @Nullable Object> T execute(CallableStatementCreator csc, CallableStatementCallback<T> action)
 			throws DataAccessException {
 
 		Assert.notNull(csc, "CallableStatementCreator must not be null");
@@ -1192,12 +1203,12 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
-	public <T> @Nullable T execute(String callString, CallableStatementCallback<T> action) throws DataAccessException {
+	public <T extends @Nullable Object> T execute(String callString, CallableStatementCallback<T> action) throws DataAccessException {
 		return execute(new SimpleCallableStatementCreator(callString), action);
 	}
 
 	@Override
-	public Map<String, Object> call(CallableStatementCreator csc, List<SqlParameter> declaredParameters)
+	public Map<String, @Nullable Object> call(CallableStatementCreator csc, List<SqlParameter> declaredParameters)
 			throws DataAccessException {
 
 		List<SqlParameter> updateCountParameters = new ArrayList<>();
@@ -1218,14 +1229,14 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 			}
 		}
 
-		Map<String, Object> result = execute(csc, cs -> {
+		Map<String, @Nullable Object> result = execute(csc, cs -> {
 			boolean retVal = cs.execute();
 			int updateCount = cs.getUpdateCount();
 			if (logger.isTraceEnabled()) {
 				logger.trace("CallableStatement.execute() returned '" + retVal + "'");
 				logger.trace("CallableStatement.getUpdateCount() returned " + updateCount);
 			}
-			Map<String, Object> resultsMap = createResultsMap();
+			Map<String, @Nullable Object> resultsMap = createResultsMap();
 			if (retVal || updateCount != -1) {
 				resultsMap.putAll(extractReturnedResults(cs, updateCountParameters, resultSetParameters, updateCount));
 			}
@@ -1244,11 +1255,11 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	 * @param resultSetParameters the parameter list of declared resultSet parameters for the stored procedure
 	 * @return a Map that contains returned results
 	 */
-	protected Map<String, Object> extractReturnedResults(CallableStatement cs,
+	protected Map<String, @Nullable Object> extractReturnedResults(CallableStatement cs,
 			@Nullable List<SqlParameter> updateCountParameters, @Nullable List<SqlParameter> resultSetParameters,
 			int updateCount) throws SQLException {
 
-		Map<String, Object> results = new LinkedHashMap<>(4);
+		Map<String, @Nullable Object> results = new LinkedHashMap<>(4);
 		int rsIndex = 0;
 		int updateIndex = 0;
 		boolean moreResults;
@@ -1307,10 +1318,10 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	 * @param parameters parameter list for the stored procedure
 	 * @return a Map that contains returned results
 	 */
-	protected Map<String, Object> extractOutputParameters(CallableStatement cs, List<SqlParameter> parameters)
+	protected Map<String, @Nullable Object> extractOutputParameters(CallableStatement cs, List<SqlParameter> parameters)
 			throws SQLException {
 
-		Map<String, Object> results = CollectionUtils.newLinkedHashMap(parameters.size());
+		Map<String, @Nullable Object> results = CollectionUtils.newLinkedHashMap(parameters.size());
 		int sqlColIndex = 1;
 		for (SqlParameter param : parameters) {
 			if (param instanceof SqlOutParameter outParam) {
@@ -1353,13 +1364,14 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	 * @param param the corresponding stored procedure parameter
 	 * @return a Map that contains returned results
 	 */
-	protected Map<String, Object> processResultSet(
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/950
+	protected Map<@Nullable String, @Nullable Object> processResultSet(
 			@Nullable ResultSet rs, ResultSetSupportingSqlParameter param) throws SQLException {
 
 		if (rs != null) {
 			try {
 				if (param.getRowMapper() != null) {
-					RowMapper<?> rowMapper = param.getRowMapper();
+					RowMapper<? extends @Nullable Object> rowMapper = param.getRowMapper();
 					Object data = (new RowMapperResultSetExtractor<>(rowMapper)).extractData(rs);
 					return Collections.singletonMap(param.getName(), data);
 				}
@@ -1391,7 +1403,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	 * @return the RowMapper to use
 	 * @see ColumnMapRowMapper
 	 */
-	protected RowMapper<Map<String, Object>> getColumnMapRowMapper() {
+	protected RowMapper<Map<String, @Nullable Object>> getColumnMapRowMapper() {
 		return new ColumnMapRowMapper();
 	}
 
@@ -1401,7 +1413,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	 * @return the RowMapper to use
 	 * @see SingleColumnRowMapper
 	 */
-	protected <T> RowMapper<T> getSingleColumnRowMapper(Class<T> requiredType) {
+	protected <T> RowMapper<@Nullable T> getSingleColumnRowMapper(Class<T> requiredType) {
 		return new SingleColumnRowMapper<>(requiredType);
 	}
 
@@ -1414,7 +1426,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	 * @see #setResultsMapCaseInsensitive
 	 * @see #isResultsMapCaseInsensitive
 	 */
-	protected Map<String, Object> createResultsMap() {
+	protected Map<String, @Nullable Object> createResultsMap() {
 		if (isResultsMapCaseInsensitive()) {
 			return new LinkedCaseInsensitiveMap<>();
 		}
@@ -1744,7 +1756,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	 * <p>Uses a regular ResultSet, so we have to be careful when using it:
 	 * We don't use it for navigating since this could lead to unpredictable consequences.
 	 */
-	private static class RowCallbackHandlerResultSetExtractor implements ResultSetExtractor<Object> {
+	private static class RowCallbackHandlerResultSetExtractor implements ResultSetExtractor<@Nullable Object> {
 
 		private final RowCallbackHandler rch;
 

spring-jdbc/src/main/java/org/springframework/jdbc/core/ParameterizedPreparedStatementSetter.java

@@ -19,6 +19,8 @@ package org.springframework.jdbc.core;
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
 
+import org.jspecify.annotations.Nullable;
+
 /**
  * Parameterized callback interface used by the {@link JdbcTemplate} class for
  * batch updates.
@@ -47,6 +49,6 @@ public interface ParameterizedPreparedStatementSetter<T> {
 	 * @param argument the object containing the values to be set
 	 * @throws SQLException if an SQLException is encountered (i.e. there is no need to catch SQLException)
 	 */
-	void setValues(PreparedStatement ps, T argument) throws SQLException;
+	void setValues(PreparedStatement ps, @Nullable T argument) throws SQLException;
 
 }

spring-jdbc/src/main/java/org/springframework/jdbc/core/PreparedStatementCallback.java

@@ -44,7 +44,7 @@ import org.springframework.dao.DataAccessException;
  * @see JdbcTemplate#execute(PreparedStatementCreator, PreparedStatementCallback)
  */
 @FunctionalInterface
-public interface PreparedStatementCallback<T> {
+public interface PreparedStatementCallback<T extends @Nullable Object> {
 
 	/**
 	 * Gets called by {@code JdbcTemplate.execute} with an active JDBC
@@ -75,6 +75,6 @@ public interface PreparedStatementCallback<T> {
 	 * @see JdbcTemplate#queryForObject(String, Class, Object...)
 	 * @see JdbcTemplate#queryForList(String, Object...)
 	 */
-	@Nullable T doInPreparedStatement(PreparedStatement ps) throws SQLException, DataAccessException;
+	T doInPreparedStatement(PreparedStatement ps) throws SQLException, DataAccessException;
 
 }

spring-jdbc/src/main/java/org/springframework/jdbc/core/ResultSetExtractor.java

@@ -50,7 +50,7 @@ import org.springframework.dao.DataAccessException;
  * @see org.springframework.jdbc.core.support.AbstractLobStreamingResultSetExtractor
  */
 @FunctionalInterface
-public interface ResultSetExtractor<T> {
+public interface ResultSetExtractor<T extends @Nullable Object> {
 
 	/**
 	 * Implementations must implement this method to process the entire ResultSet.
@@ -62,6 +62,6 @@ public interface ResultSetExtractor<T> {
 	 * values or navigating (that is, there's no need to catch SQLException)
 	 * @throws DataAccessException in case of custom exceptions
 	 */
-	@Nullable T extractData(ResultSet rs) throws SQLException, DataAccessException;
+	T extractData(ResultSet rs) throws SQLException, DataAccessException;
 
 }

spring-jdbc/src/main/java/org/springframework/jdbc/core/RowMapper.java

@@ -49,7 +49,7 @@ import org.jspecify.annotations.Nullable;
  * @see org.springframework.jdbc.object.MappingSqlQuery
  */
 @FunctionalInterface
-public interface RowMapper<T> {
+public interface RowMapper<T extends @Nullable Object> {
 
 	/**
 	 * Implementations must implement this method to map each row of data in the
@@ -61,6 +61,6 @@ public interface RowMapper<T> {
 	 * @throws SQLException if an SQLException is encountered while getting
 	 * column values (that is, there's no need to catch SQLException)
 	 */
-	@Nullable T mapRow(ResultSet rs, int rowNum) throws SQLException;
+	T mapRow(ResultSet rs, int rowNum) throws SQLException;
 
 }

spring-jdbc/src/main/java/org/springframework/jdbc/core/RowMapperResultSetExtractor.java

@@ -21,6 +21,8 @@ import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.util.Assert;
 
 /**
@@ -59,7 +61,7 @@ import org.springframework.util.Assert;
  * @see JdbcTemplate
  * @see org.springframework.jdbc.object.MappingSqlQuery
  */
-public class RowMapperResultSetExtractor<T> implements ResultSetExtractor<List<T>> {
+public class RowMapperResultSetExtractor<T extends @Nullable Object> implements ResultSetExtractor<List<T>> {
 
 	private final RowMapper<T> rowMapper;
 

spring-jdbc/src/main/java/org/springframework/jdbc/core/SingleColumnRowMapper.java

@@ -46,7 +46,7 @@ import org.springframework.util.NumberUtils;
  * @see JdbcTemplate#queryForList(String, Class)
  * @see JdbcTemplate#queryForObject(String, Class)
  */
-public class SingleColumnRowMapper<T> implements RowMapper<T> {
+public class SingleColumnRowMapper<T> implements RowMapper<@Nullable T> {
 
 	private @Nullable Class<?> requiredType;
 

spring-jdbc/src/main/java/org/springframework/jdbc/core/StatementCallback.java

@@ -37,7 +37,7 @@ import org.springframework.dao.DataAccessException;
  * @see JdbcTemplate#execute(StatementCallback)
  */
 @FunctionalInterface
-public interface StatementCallback<T> {
+public interface StatementCallback<T extends @Nullable Object> {
 
 	/**
 	 * Gets called by {@code JdbcTemplate.execute} with an active JDBC
@@ -68,6 +68,6 @@ public interface StatementCallback<T> {
 	 * @see JdbcTemplate#queryForObject(String, Class)
 	 * @see JdbcTemplate#queryForRowSet(String)
 	 */
-	@Nullable T doInStatement(Statement stmt) throws SQLException, DataAccessException;
+	T doInStatement(Statement stmt) throws SQLException, DataAccessException;
 
 }

spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/NamedParameterJdbcOperations.java

@@ -76,7 +76,7 @@ public interface NamedParameterJdbcOperations {
 	 * @return a result object returned by the action, or {@code null}
 	 * @throws DataAccessException if there is any problem
 	 */
-	<T> @Nullable T execute(String sql, SqlParameterSource paramSource, PreparedStatementCallback<T> action)
+	<T extends @Nullable Object> T execute(String sql, SqlParameterSource paramSource, PreparedStatementCallback<T> action)
 			throws DataAccessException;
 
 	/**
@@ -94,7 +94,7 @@ public interface NamedParameterJdbcOperations {
 	 * @return a result object returned by the action, or {@code null}
 	 * @throws DataAccessException if there is any problem
 	 */
-	<T> @Nullable T execute(String sql, Map<String, ?> paramMap, PreparedStatementCallback<T> action)
+	<T extends @Nullable Object> T execute(String sql, Map<String, ?> paramMap, PreparedStatementCallback<T> action)
 			throws DataAccessException;
 
 	/**
@@ -110,7 +110,7 @@ public interface NamedParameterJdbcOperations {
 	 * @return a result object returned by the action, or {@code null}
 	 * @throws DataAccessException if there is any problem
 	 */
-	<T> @Nullable T execute(String sql, PreparedStatementCallback<T> action) throws DataAccessException;
+	<T extends @Nullable Object> T execute(String sql, PreparedStatementCallback<T> action) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list
@@ -122,7 +122,7 @@ public interface NamedParameterJdbcOperations {
 	 * @return an arbitrary result object, as returned by the ResultSetExtractor
 	 * @throws DataAccessException if the query fails
 	 */
-	<T> @Nullable T query(String sql, SqlParameterSource paramSource, ResultSetExtractor<T> rse)
+	<T extends @Nullable Object> T query(String sql, SqlParameterSource paramSource, ResultSetExtractor<T> rse)
 			throws DataAccessException;
 
 	/**
@@ -136,7 +136,7 @@ public interface NamedParameterJdbcOperations {
 	 * @return an arbitrary result object, as returned by the ResultSetExtractor
 	 * @throws DataAccessException if the query fails
 	 */
-	<T> @Nullable T query(String sql, Map<String, ?> paramMap, ResultSetExtractor<T> rse)
+	<T extends @Nullable Object> T query(String sql, Map<String, ?> paramMap, ResultSetExtractor<T> rse)
 			throws DataAccessException;
 
 	/**
@@ -150,7 +150,7 @@ public interface NamedParameterJdbcOperations {
 	 * @return an arbitrary result object, as returned by the ResultSetExtractor
 	 * @throws DataAccessException if the query fails
 	 */
-	<T> @Nullable T query(String sql, ResultSetExtractor<T> rse) throws DataAccessException;
+	<T extends @Nullable Object> T query(String sql, ResultSetExtractor<T> rse) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list of
@@ -198,7 +198,7 @@ public interface NamedParameterJdbcOperations {
 	 * @return the result List, containing mapped objects
 	 * @throws DataAccessException if the query fails
 	 */
-	<T> List<T> query(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
+	<T extends @Nullable Object> List<T> query(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
 			throws DataAccessException;
 
 	/**
@@ -212,7 +212,7 @@ public interface NamedParameterJdbcOperations {
 	 * @return the result List, containing mapped objects
 	 * @throws DataAccessException if the query fails
 	 */
-	<T> List<T> query(String sql, Map<String, ?> paramMap, RowMapper<T> rowMapper)
+	<T extends @Nullable Object> List<T> query(String sql, Map<String, ?> paramMap, RowMapper<T> rowMapper)
 			throws DataAccessException;
 
 	/**
@@ -226,7 +226,7 @@ public interface NamedParameterJdbcOperations {
 	 * @return the result List, containing mapped objects
 	 * @throws DataAccessException if the query fails
 	 */
-	<T> List<T> query(String sql, RowMapper<T> rowMapper) throws DataAccessException;
+	<T extends @Nullable Object> List<T> query(String sql, RowMapper<T> rowMapper) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a list
@@ -240,7 +240,7 @@ public interface NamedParameterJdbcOperations {
 	 * @throws DataAccessException if the query fails
 	 * @since 5.3
 	 */
-	<T> Stream<T> queryForStream(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
+	<T extends @Nullable Object> Stream<T> queryForStream(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
 			throws DataAccessException;
 
 	/**
@@ -256,7 +256,7 @@ public interface NamedParameterJdbcOperations {
 	 * @throws DataAccessException if the query fails
 	 * @since 5.3
 	 */
-	<T> Stream<T> queryForStream(String sql, Map<String, ?> paramMap, RowMapper<T> rowMapper)
+	<T extends @Nullable Object> Stream<T> queryForStream(String sql, Map<String, ?> paramMap, RowMapper<T> rowMapper)
 			throws DataAccessException;
 
 	/**
@@ -272,7 +272,7 @@ public interface NamedParameterJdbcOperations {
 	 * if the query does not return exactly one row
 	 * @throws DataAccessException if the query fails
 	 */
-	<T> @Nullable T queryForObject(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
+	<T extends @Nullable Object> T queryForObject(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
 			throws DataAccessException;
 
 	/**
@@ -289,7 +289,7 @@ public interface NamedParameterJdbcOperations {
 	 * if the query does not return exactly one row
 	 * @throws DataAccessException if the query fails
 	 */
-	<T> @Nullable T queryForObject(String sql, Map<String, ?> paramMap, RowMapper<T> rowMapper)
+	<T extends @Nullable Object> T queryForObject(String sql, Map<String, ?> paramMap, RowMapper<T> rowMapper)
 			throws DataAccessException;
 
 	/**
@@ -346,7 +346,7 @@ public interface NamedParameterJdbcOperations {
 	 * @see org.springframework.jdbc.core.JdbcTemplate#queryForMap(String)
 	 * @see org.springframework.jdbc.core.ColumnMapRowMapper
 	 */
-	Map<String, Object> queryForMap(String sql, SqlParameterSource paramSource) throws DataAccessException;
+	Map<String, @Nullable Object> queryForMap(String sql, SqlParameterSource paramSource) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a
@@ -366,7 +366,7 @@ public interface NamedParameterJdbcOperations {
 	 * @see org.springframework.jdbc.core.JdbcTemplate#queryForMap(String)
 	 * @see org.springframework.jdbc.core.ColumnMapRowMapper
 	 */
-	Map<String, Object> queryForMap(String sql, Map<String, ?> paramMap) throws DataAccessException;
+	Map<String, @Nullable Object> queryForMap(String sql, Map<String, ?> paramMap) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a
@@ -382,7 +382,7 @@ public interface NamedParameterJdbcOperations {
 	 * @see org.springframework.jdbc.core.JdbcTemplate#queryForList(String, Class)
 	 * @see org.springframework.jdbc.core.SingleColumnRowMapper
 	 */
-	<T> List<T> queryForList(String sql, SqlParameterSource paramSource, Class<T> elementType)
+	<T> List<@Nullable T> queryForList(String sql, SqlParameterSource paramSource, Class<T> elementType)
 			throws DataAccessException;
 
 	/**
@@ -400,7 +400,7 @@ public interface NamedParameterJdbcOperations {
 	 * @see org.springframework.jdbc.core.JdbcTemplate#queryForList(String, Class)
 	 * @see org.springframework.jdbc.core.SingleColumnRowMapper
 	 */
-	<T> List<T> queryForList(String sql, Map<String, ?> paramMap, Class<T> elementType)
+	<T> List<@Nullable T> queryForList(String sql, Map<String, ?> paramMap, Class<T> elementType)
 			throws DataAccessException;
 
 	/**
@@ -416,7 +416,7 @@ public interface NamedParameterJdbcOperations {
 	 * @throws DataAccessException if the query fails
 	 * @see org.springframework.jdbc.core.JdbcTemplate#queryForList(String)
 	 */
-	List<Map<String, Object>> queryForList(String sql, SqlParameterSource paramSource) throws DataAccessException;
+	List<Map<String, @Nullable Object>> queryForList(String sql, SqlParameterSource paramSource) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a
@@ -432,7 +432,7 @@ public interface NamedParameterJdbcOperations {
 	 * @throws DataAccessException if the query fails
 	 * @see org.springframework.jdbc.core.JdbcTemplate#queryForList(String)
 	 */
-	List<Map<String, Object>> queryForList(String sql, Map<String, ?> paramMap) throws DataAccessException;
+	List<Map<String, @Nullable Object>> queryForList(String sql, Map<String, ?> paramMap) throws DataAccessException;
 
 	/**
 	 * Query given SQL to create a prepared statement from SQL and a

spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/NamedParameterJdbcTemplate.java

@@ -161,40 +161,40 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 
 
 	@Override
-	public <T> @Nullable T execute(String sql, SqlParameterSource paramSource, PreparedStatementCallback<T> action)
+	public <T extends @Nullable Object> T execute(String sql, SqlParameterSource paramSource, PreparedStatementCallback<T> action)
 			throws DataAccessException {
 
 		return getJdbcOperations().execute(getPreparedStatementCreator(sql, paramSource), action);
 	}
 
 	@Override
-	public <T> @Nullable T execute(String sql, Map<String, ?> paramMap, PreparedStatementCallback<T> action)
+	public <T extends @Nullable Object> T execute(String sql, Map<String, ?> paramMap, PreparedStatementCallback<T> action)
 			throws DataAccessException {
 
 		return execute(sql, new MapSqlParameterSource(paramMap), action);
 	}
 
 	@Override
-	public <T> @Nullable T execute(String sql, PreparedStatementCallback<T> action) throws DataAccessException {
+	public <T extends @Nullable Object> T execute(String sql, PreparedStatementCallback<T> action) throws DataAccessException {
 		return execute(sql, EmptySqlParameterSource.INSTANCE, action);
 	}
 
 	@Override
-	public <T> @Nullable T query(String sql, SqlParameterSource paramSource, ResultSetExtractor<T> rse)
+	public <T extends @Nullable Object> T query(String sql, SqlParameterSource paramSource, ResultSetExtractor<T> rse)
 			throws DataAccessException {
 
 		return getJdbcOperations().query(getPreparedStatementCreator(sql, paramSource), rse);
 	}
 
 	@Override
-	public <T> @Nullable T query(String sql, Map<String, ?> paramMap, ResultSetExtractor<T> rse)
+	public <T extends @Nullable Object> T query(String sql, Map<String, ?> paramMap, ResultSetExtractor<T> rse)
 			throws DataAccessException {
 
 		return query(sql, new MapSqlParameterSource(paramMap), rse);
 	}
 
 	@Override
-	public <T> @Nullable T query(String sql, ResultSetExtractor<T> rse) throws DataAccessException {
+	public <T extends @Nullable Object> T query(String sql, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(sql, EmptySqlParameterSource.INSTANCE, rse);
 	}
 
@@ -218,14 +218,14 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
-	public <T> List<T> query(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
+	public <T extends @Nullable Object> List<T> query(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
 			throws DataAccessException {
 
 		return getJdbcOperations().query(getPreparedStatementCreator(sql, paramSource), rowMapper);
 	}
 
 	@Override
-	public <T> List<T> query(String sql, Map<String, ?> paramMap, RowMapper<T> rowMapper)
+	public <T extends @Nullable Object> List<T> query(String sql, Map<String, ?> paramMap, RowMapper<T> rowMapper)
 			throws DataAccessException {
 
 		return query(sql, new MapSqlParameterSource(paramMap), rowMapper);
@@ -237,21 +237,21 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
-	public <T> Stream<T> queryForStream(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
+	public <T extends @Nullable Object> Stream<T> queryForStream(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
 			throws DataAccessException {
 
 		return getJdbcOperations().queryForStream(getPreparedStatementCreator(sql, paramSource), rowMapper);
 	}
 
 	@Override
-	public <T> Stream<T> queryForStream(String sql, Map<String, ?> paramMap, RowMapper<T> rowMapper)
+	public <T extends @Nullable Object> Stream<T> queryForStream(String sql, Map<String, ?> paramMap, RowMapper<T> rowMapper)
 			throws DataAccessException {
 
 		return queryForStream(sql, new MapSqlParameterSource(paramMap), rowMapper);
 	}
 
 	@Override
-	public <T> @Nullable T queryForObject(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
+	public <T extends @Nullable Object> T queryForObject(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
 			throws DataAccessException {
 
 		List<T> results = getJdbcOperations().query(getPreparedStatementCreator(sql, paramSource), rowMapper);
@@ -259,7 +259,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
-	public <T> @Nullable T queryForObject(String sql, Map<String, ?> paramMap, RowMapper<T>rowMapper)
+	public <T extends @Nullable Object> T queryForObject(String sql, Map<String, ?> paramMap, RowMapper<T>rowMapper)
 			throws DataAccessException {
 
 		return queryForObject(sql, new MapSqlParameterSource(paramMap), rowMapper);
@@ -280,42 +280,44 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
-	public Map<String, Object> queryForMap(String sql, SqlParameterSource paramSource) throws DataAccessException {
+	public Map<String, @Nullable Object> queryForMap(String sql, SqlParameterSource paramSource) throws DataAccessException {
-		Map<String, Object> result = queryForObject(sql, paramSource, new ColumnMapRowMapper());
+		Map<String, @Nullable Object> result = queryForObject(sql, paramSource, new ColumnMapRowMapper());
 		Assert.state(result != null, "No result map");
 		return result;
 	}
 
 	@Override
-	public Map<String, Object> queryForMap(String sql, Map<String, ?> paramMap) throws DataAccessException {
+	public Map<String, @Nullable Object> queryForMap(String sql, Map<String, ?> paramMap) throws DataAccessException {
-		Map<String, Object> result = queryForObject(sql, paramMap, new ColumnMapRowMapper());
+		Map<String, @Nullable Object> result = queryForObject(sql, paramMap, new ColumnMapRowMapper());
 		Assert.state(result != null, "No result map");
 		return result;
 	}
 
 	@Override
-	public <T> List<T> queryForList(String sql, SqlParameterSource paramSource, Class<T> elementType)
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
+	public <T> List<@Nullable T> queryForList(String sql, SqlParameterSource paramSource, Class<T> elementType)
 			throws DataAccessException {
 
 		return query(sql, paramSource, new SingleColumnRowMapper<>(elementType));
 	}
 
 	@Override
-	public <T> List<T> queryForList(String sql, Map<String, ?> paramMap, Class<T> elementType)
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
+	public <T> List<@Nullable T> queryForList(String sql, Map<String, ?> paramMap, Class<T> elementType)
 			throws DataAccessException {
 
 		return queryForList(sql, new MapSqlParameterSource(paramMap), elementType);
 	}
 
 	@Override
-	public List<Map<String, Object>> queryForList(String sql, SqlParameterSource paramSource)
+	public List<Map<String, @Nullable Object>> queryForList(String sql, SqlParameterSource paramSource)
 			throws DataAccessException {
 
 		return query(sql, paramSource, new ColumnMapRowMapper());
 	}
 
 	@Override
-	public List<Map<String, Object>> queryForList(String sql, Map<String, ?> paramMap)
+	public List<Map<String, @Nullable Object>> queryForList(String sql, Map<String, ?> paramMap)
 			throws DataAccessException {
 
 		return queryForList(sql, new MapSqlParameterSource(paramMap));

spring-jdbc/src/main/java/org/springframework/jdbc/core/simple/AbstractJdbcCall.java

@@ -379,7 +379,7 @@ public abstract class AbstractJdbcCall {
 	 * @param parameterSource parameter names and values to be used in call
 	 * @return a Map of out parameters
 	 */
-	protected Map<String, Object> doExecute(SqlParameterSource parameterSource) {
+	protected Map<String, @Nullable Object> doExecute(SqlParameterSource parameterSource) {
 		checkCompiled();
 		Map<String, Object> params = matchInParameterValuesWithCallParameters(parameterSource);
 		return executeCallInternal(params);
@@ -391,7 +391,7 @@ public abstract class AbstractJdbcCall {
 	 * declared for the stored procedure.
 	 * @return a Map of out parameters
 	 */
-	protected Map<String, Object> doExecute(Object... args) {
+	protected Map<String, @Nullable Object> doExecute(Object... args) {
 		checkCompiled();
 		Map<String, ?> params = matchInParameterValuesWithCallParameters(args);
 		return executeCallInternal(params);
@@ -402,7 +402,7 @@ public abstract class AbstractJdbcCall {
 	 * @param args a Map of parameter name and values
 	 * @return a Map of out parameters
 	 */
-	protected Map<String, Object> doExecute(Map<String, ?> args) {
+	protected Map<String, @Nullable Object> doExecute(Map<String, ?> args) {
 		checkCompiled();
 		Map<String, ?> params = matchInParameterValuesWithCallParameters(args);
 		return executeCallInternal(params);
@@ -411,7 +411,7 @@ public abstract class AbstractJdbcCall {
 	/**
 	 * Delegate method to perform the actual call processing.
 	 */
-	private Map<String, Object> executeCallInternal(Map<String, ?> args) {
+	private Map<String, @Nullable Object> executeCallInternal(Map<String, ?> args) {
 		CallableStatementCreator csc = getCallableStatementFactory().newCallableStatementCreator(args);
 		if (logger.isDebugEnabled()) {
 			logger.debug("The following parameters are used for call " + getCallString() + " with " + args);

spring-jdbc/src/main/java/org/springframework/jdbc/core/simple/AbstractJdbcInsert.java

@@ -448,6 +448,7 @@ public abstract class AbstractJdbcInsert {
 	/**
 	 * Delegate method to execute the insert, generating any number of keys.
 	 */
+	@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
 	private KeyHolder executeInsertAndReturnKeyHolderInternal(List<?> values) {
 		if (logger.isDebugEnabled()) {
 			logger.debug("The following parameters are used for call " + getInsertString() + " with: " + values);
@@ -496,7 +497,7 @@ public abstract class AbstractJdbcInsert {
 				keyHolder.getKeyList().add(keys);
 			}
 			else {
-				getJdbcTemplate().execute((ConnectionCallback<Object>) con -> {
+				getJdbcTemplate().execute((ConnectionCallback<@Nullable Object>) con -> {
 					// Do the insert
 					PreparedStatement ps = null;
 					try {

spring-jdbc/src/main/java/org/springframework/jdbc/core/simple/DefaultJdbcClient.java

@@ -239,18 +239,18 @@ final class DefaultJdbcClient implements JdbcClient {
 					new IndexedParamResultQuerySpec());
 		}
 
-		@SuppressWarnings("unchecked")
 		@Override
-		public <T> MappedQuerySpec<T> query(Class<T> mappedClass) {
+		@SuppressWarnings({"unchecked", "NullAway"}) // See https://github.com/uber/NullAway/issues/1075
+		public <T> MappedQuerySpec<@Nullable T> query(Class<T> mappedClass) {
 			RowMapper<?> rowMapper = rowMapperCache.computeIfAbsent(mappedClass, key ->
 					BeanUtils.isSimpleProperty(mappedClass) ?
 							new SingleColumnRowMapper<>(mappedClass, conversionService) :
 							new SimplePropertyRowMapper<>(mappedClass, conversionService));
-			return query((RowMapper<T>) rowMapper);
+			return query((RowMapper<@Nullable T>) rowMapper);
 		}
 
 		@Override
-		public <T> MappedQuerySpec<T> query(RowMapper<T> rowMapper) {
+		public <T extends @Nullable Object> MappedQuerySpec<T> query(RowMapper<T> rowMapper) {
 			return (useNamedParams() ?
 					new NamedParamMappedQuerySpec<>(rowMapper) :
 					new IndexedParamMappedQuerySpec<>(rowMapper));
@@ -267,7 +267,7 @@ final class DefaultJdbcClient implements JdbcClient {
 		}
 
 		@Override
-		public <T> T query(ResultSetExtractor<T> rse) {
+		public <T extends @Nullable Object> T query(ResultSetExtractor<T> rse) {
 			T result = (useNamedParams() ?
 					this.namedParamOps.query(this.sql, this.namedParamSource, rse) :
 					this.classicOps.query(statementCreatorForIndexedParams(), rse));
@@ -332,17 +332,18 @@ final class DefaultJdbcClient implements JdbcClient {
 			}
 
 			@Override
-			public List<Map<String, Object>> listOfRows() {
+			public List<Map<String, @Nullable Object>> listOfRows() {
 				return classicOps.queryForList(sql, indexedParams.toArray());
 			}
 
 			@Override
-			public Map<String, Object> singleRow() {
+			public Map<String, @Nullable Object> singleRow() {
 				return classicOps.queryForMap(sql, indexedParams.toArray());
 			}
 
 			@Override
-			public List<Object> singleColumn() {
+			@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
+			public List<@Nullable Object> singleColumn() {
 				return classicOps.queryForList(sql, Object.class, indexedParams.toArray());
 			}
 		}
@@ -356,23 +357,25 @@ final class DefaultJdbcClient implements JdbcClient {
 			}
 
 			@Override
-			public List<Map<String, Object>> listOfRows() {
+			public List<Map<String, @Nullable Object>> listOfRows() {
 				return namedParamOps.queryForList(sql, namedParamSource);
 			}
 
 			@Override
-			public Map<String, Object> singleRow() {
+			@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
+			public Map<String, @Nullable Object> singleRow() {
 				return namedParamOps.queryForMap(sql, namedParamSource);
 			}
 
 			@Override
-			public List<Object> singleColumn() {
+			@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
+			public List<@Nullable Object> singleColumn() {
 				return namedParamOps.queryForList(sql, namedParamSource, Object.class);
 			}
 		}
 
 
-		private class IndexedParamMappedQuerySpec<T> implements MappedQuerySpec<T> {
+		private class IndexedParamMappedQuerySpec<T extends @Nullable Object> implements MappedQuerySpec<T> {
 
 			private final RowMapper<T> rowMapper;
 
@@ -392,7 +395,7 @@ final class DefaultJdbcClient implements JdbcClient {
 		}
 
 
-		private class NamedParamMappedQuerySpec<T> implements MappedQuerySpec<T> {
+		private class NamedParamMappedQuerySpec<T extends @Nullable Object> implements MappedQuerySpec<T> {
 
 			private final RowMapper<T> rowMapper;
 

spring-jdbc/src/main/java/org/springframework/jdbc/core/simple/JdbcClient.java

@@ -26,6 +26,7 @@ import java.util.stream.Stream;
 
 import javax.sql.DataSource;
 
+import org.jspecify.annotations.NonNull;
 import org.jspecify.annotations.Nullable;
 
 import org.springframework.core.convert.ConversionService;
@@ -286,7 +287,7 @@ public interface JdbcClient {
 		 * @see org.springframework.jdbc.core.SingleColumnRowMapper
 		 * @see org.springframework.jdbc.core.SimplePropertyRowMapper
 		 */
-		<T> MappedQuerySpec<T> query(Class<T> mappedClass);
+		<T> MappedQuerySpec<@Nullable T> query(Class<T> mappedClass);
 
 		/**
 		 * Proceed towards execution of a mapped query, with several options
@@ -295,7 +296,7 @@ public interface JdbcClient {
 		 * @return the mapped query specification
 		 * @see java.sql.PreparedStatement#executeQuery()
 		 */
-		<T> MappedQuerySpec<T> query(RowMapper<T> rowMapper);
+		<T extends @Nullable Object> MappedQuerySpec<T> query(RowMapper<T> rowMapper);
 
 		/**
 		 * Execute a query with the provided SQL statement,
@@ -312,7 +313,7 @@ public interface JdbcClient {
 		 * @return the value returned by the ResultSetExtractor
 		 * @see java.sql.PreparedStatement#executeQuery()
 		 */
-		<T> T query(ResultSetExtractor<T> rse);
+		<T extends @Nullable Object> T query(ResultSetExtractor<T> rse);
 
 		/**
 		 * Execute the provided SQL statement as an update.
@@ -365,14 +366,14 @@ public interface JdbcClient {
 		 * with each result row represented as a map of
 		 * case-insensitive column names to column values
 		 */
-		List<Map<String, Object>> listOfRows();
+		List<Map<String, @Nullable Object>> listOfRows();
 
 		/**
 		 * Retrieve a single row result.
 		 * @return the result row represented as a map of
 		 * case-insensitive column names to column values
 		 */
-		Map<String, Object> singleRow();
+		Map<String, @Nullable Object> singleRow();
 
 		/**
 		 * Retrieve a single column result,
@@ -380,7 +381,7 @@ public interface JdbcClient {
 		 * @return a (potentially empty) list of rows, with each
 		 * row represented as its single column value
 		 */
-		List<Object> singleColumn();
+		List<@Nullable Object> singleColumn();
 
 		/**
 		 * Retrieve a single value result.
@@ -390,6 +391,7 @@ public interface JdbcClient {
 		 * @see #optionalValue()
 		 * @see DataAccessUtils#requiredSingleResult(Collection)
 		 */
+		@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
 		default Object singleValue() {
 			return DataAccessUtils.requiredSingleResult(singleColumn());
 		}
@@ -401,6 +403,7 @@ public interface JdbcClient {
 		 * @see #singleValue()
 		 * @see DataAccessUtils#optionalResult(Collection)
 		 */
+		@SuppressWarnings("NullAway") // See https://github.com/uber/NullAway/issues/1075
 		default Optional<Object> optionalValue() {
 			return DataAccessUtils.optionalResult(singleColumn());
 		}
@@ -412,7 +415,7 @@ public interface JdbcClient {
 	 *
 	 * @param <T> the RowMapper-declared result type
 	 */
-	interface MappedQuerySpec<T> {
+	interface MappedQuerySpec<T extends @Nullable Object> {
 
 		/**
 		 * Retrieve the result as a lazily resolved stream of mapped objects,
@@ -447,7 +450,7 @@ public interface JdbcClient {
 		 * @see #optional()
 		 * @see DataAccessUtils#requiredSingleResult(Collection)
 		 */
-		default T single() {
+		default @NonNull T single() {
 			return DataAccessUtils.requiredSingleResult(list());
 		}
 
@@ -457,7 +460,7 @@ public interface JdbcClient {
 		 * @see #single()
 		 * @see DataAccessUtils#optionalResult(Collection)
 		 */
-		default Optional<T> optional() {
+		default Optional<@NonNull T> optional() {
 			return DataAccessUtils.optionalResult(list());
 		}
 	}

spring-jdbc/src/main/java/org/springframework/jdbc/core/simple/SimpleJdbcCall.java

@@ -186,17 +186,17 @@ public class SimpleJdbcCall extends AbstractJdbcCall implements SimpleJdbcCallOp
 	}
 
 	@Override
-	public Map<String, Object> execute(Object... args) {
+	public Map<String, @Nullable Object> execute(Object... args) {
 		return doExecute(args);
 	}
 
 	@Override
-	public Map<String, Object> execute(Map<String, ?> args) {
+	public Map<String, @Nullable Object> execute(Map<String, ?> args) {
 		return doExecute(args);
 	}
 
 	@Override
-	public Map<String, Object> execute(SqlParameterSource parameterSource) {
+	public Map<String, @Nullable Object> execute(SqlParameterSource parameterSource) {
 		return doExecute(parameterSource);
 	}
 

spring-jdbc/src/main/java/org/springframework/jdbc/core/simple/SimpleJdbcCallOperations.java

@@ -174,7 +174,7 @@ public interface SimpleJdbcCallOperations {
 	 * the stored procedure.
 	 * @return a Map of output params
 	 */
-	Map<String, Object> execute(Object... args);
+	Map<String, @Nullable Object> execute(Object... args);
 
 	/**
 	 * Execute the stored procedure and return a map of output params, keyed by name
@@ -182,7 +182,7 @@ public interface SimpleJdbcCallOperations {
 	 * @param args a Map containing the parameter values to be used in the call
 	 * @return a Map of output params
 	 */
-	Map<String, Object> execute(Map<String, ?> args);
+	Map<String, @Nullable Object> execute(Map<String, ?> args);
 
 	/**
 	 * Execute the stored procedure and return a map of output params, keyed by name
@@ -190,6 +190,6 @@ public interface SimpleJdbcCallOperations {
 	 * @param args the SqlParameterSource containing the parameter values to be used in the call
 	 * @return a Map of output params
 	 */
-	Map<String, Object> execute(SqlParameterSource args);
+	Map<String, @Nullable Object> execute(SqlParameterSource args);
 
 }

spring-jdbc/src/main/java/org/springframework/jdbc/core/support/AbstractLobStreamingResultSetExtractor.java

@@ -59,7 +59,7 @@ import org.springframework.jdbc.core.ResultSetExtractor;
  * in favor of {@link ResultSet#getBinaryStream}/{@link ResultSet#getCharacterStream} usage
  */
 @Deprecated(since = "6.2")
-public abstract class AbstractLobStreamingResultSetExtractor<T> implements ResultSetExtractor<T> {
+public abstract class AbstractLobStreamingResultSetExtractor<T> implements ResultSetExtractor<@Nullable T> {
 
 	/**
 	 * Delegates to handleNoRowFound, handleMultipleRowsFound and streamData,

spring-jdbc/src/main/java/org/springframework/jdbc/object/GenericSqlQuery.java

@@ -35,7 +35,7 @@ import org.springframework.util.Assert;
  * @see #setRowMapper
  * @see #setRowMapperClass
  */
-public class GenericSqlQuery<T> extends SqlQuery<T> {
+public class GenericSqlQuery<T extends @Nullable Object> extends SqlQuery<T> {
 
 	private @Nullable RowMapper<T> rowMapper;
 

spring-jdbc/src/main/java/org/springframework/jdbc/object/MappingSqlQuery.java

@@ -39,7 +39,7 @@ import org.jspecify.annotations.Nullable;
  * @param <T> the result type
  * @see MappingSqlQueryWithParameters
  */
-public abstract class MappingSqlQuery<T> extends MappingSqlQueryWithParameters<T> {
+public abstract class MappingSqlQuery<T extends @Nullable Object> extends MappingSqlQueryWithParameters<T> {
 
 	/**
 	 * Constructor that allows use as a JavaBean.
@@ -63,7 +63,7 @@ public abstract class MappingSqlQuery<T> extends MappingSqlQueryWithParameters<T
 	 * @see #mapRow(ResultSet, int)
 	 */
 	@Override
-	protected final @Nullable T mapRow(ResultSet rs, int rowNum, @Nullable Object @Nullable [] parameters, @Nullable Map<?, ?> context)
+	protected final T mapRow(ResultSet rs, int rowNum, @Nullable Object @Nullable [] parameters, @Nullable Map<?, ?> context)
 			throws SQLException {
 
 		return mapRow(rs, rowNum);
@@ -82,6 +82,6 @@ public abstract class MappingSqlQuery<T> extends MappingSqlQueryWithParameters<T
 	 * Subclasses can simply not catch SQLExceptions, relying on the
 	 * framework to clean up.
 	 */
-	protected abstract @Nullable T mapRow(ResultSet rs, int rowNum) throws SQLException;
+	protected abstract T mapRow(ResultSet rs, int rowNum) throws SQLException;
 
 }

spring-jdbc/src/main/java/org/springframework/jdbc/object/MappingSqlQueryWithParameters.java

@@ -51,7 +51,7 @@ import org.springframework.jdbc.core.RowMapper;
  * @see org.springframework.jdbc.object.MappingSqlQuery
  * @see org.springframework.jdbc.object.SqlQuery
  */
-public abstract class MappingSqlQueryWithParameters<T> extends SqlQuery<T> {
+public abstract class MappingSqlQueryWithParameters<T extends @Nullable Object> extends SqlQuery<T> {
 
 	/**
 	 * Constructor to allow use as a JavaBean.
@@ -93,7 +93,7 @@ public abstract class MappingSqlQueryWithParameters<T> extends SqlQuery<T> {
 	 * Subclasses can simply not catch SQLExceptions, relying on the
 	 * framework to clean up.
 	 */
-	protected abstract @Nullable T mapRow(ResultSet rs, int rowNum, @Nullable Object @Nullable [] parameters, @Nullable Map<?, ?> context)
+	protected abstract T mapRow(ResultSet rs, int rowNum, @Nullable Object @Nullable [] parameters, @Nullable Map<?, ?> context)
 			throws SQLException;
 
 
@@ -116,7 +116,7 @@ public abstract class MappingSqlQueryWithParameters<T> extends SqlQuery<T> {
 		}
 
 		@Override
-		public @Nullable T mapRow(ResultSet rs, int rowNum) throws SQLException {
+		public T mapRow(ResultSet rs, int rowNum) throws SQLException {
 			return MappingSqlQueryWithParameters.this.mapRow(rs, rowNum, this.params, this.context);
 		}
 	}

spring-jdbc/src/main/java/org/springframework/jdbc/object/SqlFunction.java

@@ -51,7 +51,7 @@ import org.springframework.jdbc.core.SingleColumnRowMapper;
  * @param <T> the result type
  * @see StoredProcedure
  */
-public class SqlFunction<T> extends MappingSqlQuery<T> {
+public class SqlFunction<T> extends MappingSqlQuery<@Nullable T> {
 
 	private final SingleColumnRowMapper<T> rowMapper = new SingleColumnRowMapper<>();
 

spring-jdbc/src/main/java/org/springframework/jdbc/object/SqlQuery.java

@@ -59,7 +59,7 @@ import org.springframework.jdbc.core.namedparam.ParsedSql;
  * @param <T> the result type
  * @see SqlUpdate
  */
-public abstract class SqlQuery<T> extends SqlOperation {
+public abstract class SqlQuery<T extends @Nullable Object> extends SqlOperation {
 
 	/**
 	 * Constructor to allow use as a JavaBean.

spring-jdbc/src/main/java/org/springframework/jdbc/object/StoredProcedure.java

@@ -21,6 +21,8 @@ import java.util.Map;
 
 import javax.sql.DataSource;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
 import org.springframework.jdbc.core.JdbcTemplate;
@@ -109,8 +111,8 @@ public abstract class StoredProcedure extends SqlCall {
 	 * Output parameters will appear here, with their values after the stored procedure
 	 * has been called.
 	 */
-	public Map<String, Object> execute(Object... inParams) {
+	public Map<String, @Nullable Object> execute(Object... inParams) {
-		Map<String, Object> paramsToUse = new HashMap<>();
+		Map<String, @Nullable Object> paramsToUse = new HashMap<>();
 		validateParameters(inParams);
 		int i = 0;
 		for (SqlParameter sqlParameter : getDeclaredParameters()) {
@@ -135,7 +137,7 @@ public abstract class StoredProcedure extends SqlCall {
 	 * Output parameters will appear here, with their values after the
 	 * stored procedure has been called.
 	 */
-	public Map<String, Object> execute(Map<String, ?> inParams) throws DataAccessException {
+	public Map<String, @Nullable Object> execute(Map<String, ?> inParams) throws DataAccessException {
 		validateParameters(inParams.values().toArray());
 		return getJdbcTemplate().call(newCallableStatementCreator(inParams), getDeclaredParameters());
 	}
@@ -156,7 +158,7 @@ public abstract class StoredProcedure extends SqlCall {
 	 * Output parameters will appear here, with their values after the
 	 * stored procedure has been called.
 	 */
-	public Map<String, Object> execute(ParameterMapper inParamMapper) throws DataAccessException {
+	public Map<String, @Nullable Object> execute(ParameterMapper inParamMapper) throws DataAccessException {
 		checkCompiled();
 		return getJdbcTemplate().call(newCallableStatementCreator(inParamMapper), getDeclaredParameters());
 	}

spring-jdbc/src/main/java/org/springframework/jdbc/support/DatabaseMetaDataCallback.java

@@ -19,6 +19,8 @@ package org.springframework.jdbc.support;
 import java.sql.DatabaseMetaData;
 import java.sql.SQLException;
 
+import org.jspecify.annotations.Nullable;
+
 /**
  * A callback interface used by the JdbcUtils class. Implementations of this
  * interface perform the actual work of extracting database meta-data, but
@@ -31,7 +33,7 @@ import java.sql.SQLException;
  * @see JdbcUtils#extractDatabaseMetaData(javax.sql.DataSource, DatabaseMetaDataCallback)
  */
 @FunctionalInterface
-public interface DatabaseMetaDataCallback<T> {
+public interface DatabaseMetaDataCallback<T extends @Nullable Object> {
 
 	/**
 	 * Implementations must implement this method to process the meta-data

spring-jdbc/src/main/java/org/springframework/jdbc/support/JdbcUtils.java

@@ -321,7 +321,7 @@ public abstract class JdbcUtils {
 	 * @throws MetaDataAccessException if meta-data access failed
 	 * @see java.sql.DatabaseMetaData
 	 */
-	public static <T> T extractDatabaseMetaData(DataSource dataSource, DatabaseMetaDataCallback<T> action)
+	public static <T extends @Nullable Object> T extractDatabaseMetaData(DataSource dataSource, DatabaseMetaDataCallback<T> action)
 			throws MetaDataAccessException {
 
 		Connection con = null;

spring-jdbc/src/main/kotlin/org/springframework/jdbc/core/JdbcOperationsExtensions.kt

@@ -35,7 +35,7 @@ inline fun <reified T> JdbcOperations.queryForObject(sql: String): T =
  * @since 5.0
  */
 inline fun <reified T> JdbcOperations.queryForObject(sql: String, vararg args: Any, crossinline function: (ResultSet, Int) -> T): T =
-		queryForObject(sql, { resultSet, i -> function(resultSet, i) }, *args) as T
+		queryForObject(sql, { resultSet, i -> function(resultSet, i) }, *args)
 
 /**
  * Extension for [JdbcOperations.queryForObject] providing a
@@ -44,7 +44,7 @@ inline fun <reified T> JdbcOperations.queryForObject(sql: String, vararg args: A
  * @author Mario Arias
  * @since 5.0
  */
-inline fun <reified T> JdbcOperations.queryForObject(sql: String, args: Array<out Any>, argTypes: IntArray): T? =
+inline fun <reified T> JdbcOperations.queryForObject(sql: String, args: Array<out Any>, argTypes: IntArray): T =
 		queryForObject(sql, args, argTypes, T::class.java as Class<*>) as T
 
 /**
@@ -54,7 +54,7 @@ inline fun <reified T> JdbcOperations.queryForObject(sql: String, args: Array<ou
  * @author Mario Arias
  * @since 5.0
  */
-inline fun <reified T> JdbcOperations.queryForObject(sql: String, args: Array<out Any>): T? =
+inline fun <reified T> JdbcOperations.queryForObject(sql: String, args: Array<out Any>): T =
 		queryForObject(sql, T::class.java as Class<*>, args) as T
 
 /**
@@ -63,8 +63,9 @@ inline fun <reified T> JdbcOperations.queryForObject(sql: String, args: Array<ou
  * @author Mario Arias
  * @since 5.0
  */
-inline fun <reified T : Any> JdbcOperations.queryForList(sql: String): List<T> =
+@Suppress("UNCHECKED_CAST")
-		queryForList(sql, T::class.java)
+inline fun <reified T> JdbcOperations.queryForList(sql: String): List<T> =
+		queryForList(sql, T::class.java) as List<T>
 
 /**
  * Extension for [JdbcOperations.queryForList] providing a
@@ -73,9 +74,10 @@ inline fun <reified T : Any> JdbcOperations.queryForList(sql: String): List<T> =
  * @author Mario Arias
  * @since 5.0
  */
-inline fun <reified T : Any> JdbcOperations.queryForList(sql: String, args: Array<out Any>,
+@Suppress("UNCHECKED_CAST")
+inline fun <reified T> JdbcOperations.queryForList(sql: String, args: Array<out Any>,
 												   argTypes: IntArray): List<T> =
-		queryForList(sql, args, argTypes, T::class.java)
+		queryForList(sql, args, argTypes, T::class.java) as List<T>
 
 /**
  * Extension for [JdbcOperations.queryForList] providing a
@@ -84,8 +86,9 @@ inline fun <reified T : Any> JdbcOperations.queryForList(sql: String, args: Arra
  * @author Mario Arias
  * @since 5.0
  */
-inline fun <reified T : Any> JdbcOperations.queryForList(sql: String, args: Array<out Any>): List<T> =
+@Suppress("UNCHECKED_CAST")
-		queryForList(sql, T::class.java, args)
+inline fun <reified T> JdbcOperations.queryForList(sql: String, args: Array<out Any>): List<T> =
+		queryForList(sql, T::class.java, args) as List<T>
 
 
 /**
@@ -95,9 +98,9 @@ inline fun <reified T : Any> JdbcOperations.queryForList(sql: String, args: Arra
  * @author Mario Arias
  * @since 5.0
  */
-inline fun <reified T> JdbcOperations.query(sql: String, vararg args: Any,
+fun <T> JdbcOperations.query(sql: String, vararg args: Any,
-		crossinline function: (ResultSet) -> T): T =
+		function: (ResultSet) -> T): T =
-		query(sql, ResultSetExtractor { function(it) }, *args) as T
+		query(sql, ResultSetExtractor { function(it) }, *args)
 
 /**
  * Extension for [JdbcOperations.query] providing a RowCallbackHandler-like function

spring-jdbc/src/test/kotlin/org/springframework/jdbc/core/JdbcOperationsExtensionsTests.kt

@@ -43,6 +43,13 @@ class JdbcOperationsExtensionsTests {
 		verify { template.queryForObject(sql, any<Class<Int>>()) }
 	}
 
+	@Test
+	fun `queryForObject with nullable reified type parameters`() {
+		every { template.queryForObject(sql, any<Class<Int>>()) } returns null
+		assertThat(template.queryForObject<Int?>(sql)).isNull()
+		verify { template.queryForObject(sql, any<Class<Int>>()) }
+	}
+
 	@Test
 	fun `queryForObject with RowMapper-like function`() {
 		every { template.queryForObject(sql, any<RowMapper<Int>>(), any<Int>()) } returns 2
@@ -52,9 +59,9 @@ class JdbcOperationsExtensionsTests {
 
 	@Test  // gh-22682
 	fun `queryForObject with nullable RowMapper-like function`() {
-		every { template.queryForObject(sql, any<RowMapper<Int>>(), 3) } returns null
+		every { template.queryForObject(sql, any<RowMapper<Int?>>(), 3) } returns null
 		assertThat(template.queryForObject<Int?>(sql, 3) { _, _ -> null }).isNull()
-		verify { template.queryForObject(eq(sql), any<RowMapper<Int>>(), eq(3)) }
+		verify { template.queryForObject(eq(sql), any<RowMapper<Int?>>(), eq(3)) }
 	}
 
 	@Test
@@ -66,6 +73,15 @@ class JdbcOperationsExtensionsTests {
 		verify { template.queryForObject(sql, args, argTypes, any<Class<Int>>()) }
 	}
 
+	@Test
+	fun `queryForObject with nullable reified type parameters and argTypes`() {
+		val args = arrayOf(3)
+		val argTypes = intArrayOf(JDBCType.INTEGER.vendorTypeNumber)
+		every { template.queryForObject(sql, args, argTypes, any<Class<Int>>()) } returns null
+		assertThat(template.queryForObject<Int?>(sql, args, argTypes)).isNull()
+		verify { template.queryForObject(sql, args, argTypes, any<Class<Int>>()) }
+	}
+
 	@Test
 	fun `queryForObject with reified type parameters and args`() {
 		val args = arrayOf(3, 4)
@@ -74,6 +90,14 @@ class JdbcOperationsExtensionsTests {
 		verify { template.queryForObject(sql, any<Class<Int>>(), args) }
 	}
 
+	@Test
+	fun `queryForObject with nullable reified type parameters and args`() {
+		val args = arrayOf(3, 4)
+		every { template.queryForObject(sql, any<Class<Int>>(), args) } returns null
+		assertThat(template.queryForObject<Int?>(sql, args)).isNull()
+		verify { template.queryForObject(sql, any<Class<Int>>(), args) }
+	}
+
 	@Test
 	fun `queryForList with reified type parameters`() {
 		val list = listOf(1, 2, 3)
@@ -82,6 +106,14 @@ class JdbcOperationsExtensionsTests {
 		verify { template.queryForList(sql, any<Class<Int>>()) }
 	}
 
+	@Test
+	fun `queryForList with nullable reified type parameters`() {
+		val list = listOf(1, null, 3)
+		every { template.queryForList(sql, any<Class<Int>>()) } returns list
+		assertThat(template.queryForList<Int?>(sql)).isEqualTo(list)
+		verify { template.queryForList(sql, any<Class<Int>>()) }
+	}
+
 	@Test
 	fun `queryForList with reified type parameters and argTypes`() {
 		val list = listOf(1, 2, 3)
@@ -92,6 +124,16 @@ class JdbcOperationsExtensionsTests {
 		verify { template.queryForList(sql, args, argTypes, any<Class<Int>>()) }
 	}
 
+	@Test
+	fun `queryForList with nullable reified type parameters and argTypes`() {
+		val list = listOf(1, null, 3)
+		val args = arrayOf(3)
+		val argTypes = intArrayOf(JDBCType.INTEGER.vendorTypeNumber)
+		every { template.queryForList(sql, args, argTypes, any<Class<Int>>()) } returns list
+		assertThat(template.queryForList<Int?>(sql, args, argTypes)).isEqualTo(list)
+		verify { template.queryForList(sql, args, argTypes, any<Class<Int>>()) }
+	}
+
 	@Test
 	fun `queryForList with reified type parameters and args`() {
 		val list = listOf(1, 2, 3)
@@ -101,6 +143,15 @@ class JdbcOperationsExtensionsTests {
 		verify { template.queryForList(sql, any<Class<Int>>(), args) }
 	}
 
+	@Test
+	fun `queryForList with nullable reified type parameters and args`() {
+		val list = listOf(1, null, 3)
+		val args = arrayOf(3, 4)
+		every { template.queryForList(sql, any<Class<Int>>(), args) } returns list
+		template.queryForList<Int?>(sql, args)
+		verify { template.queryForList(sql, any<Class<Int>>(), args) }
+	}
+
 	@Test
 	fun `query with ResultSetExtractor-like function`() {
 		every { template.query(eq(sql), any<ResultSetExtractor<Int>>(), eq(3)) } returns 2
@@ -113,12 +164,11 @@ class JdbcOperationsExtensionsTests {
 
 	@Test  // gh-22682
 	fun `query with nullable ResultSetExtractor-like function`() {
-		every { template.query(eq(sql), any<ResultSetExtractor<Int>>(), eq(3)) } returns null
+		every { template.query(eq(sql), any<ResultSetExtractor<Int?>>(), eq(3)) } returns null
 		assertThat(template.query<Int?>(sql, 3) { _ -> null }).isNull()
-		verify { template.query(eq(sql), any<ResultSetExtractor<Int>>(), eq(3)) }
+		verify { template.query(eq(sql), any<ResultSetExtractor<Int?>>(), eq(3)) }
 	}
 
-	@Suppress("RemoveExplicitTypeArguments")
 	@Test
 	fun `query with RowCallbackHandler-like function`() {
 		every { template.query(sql, ofType<RowCallbackHandler>(), 3) } returns Unit
@@ -131,11 +181,21 @@ class JdbcOperationsExtensionsTests {
 	@Test
 	fun `query with RowMapper-like function`() {
 		val list = mutableListOf(1, 2, 3)
-		every { template.query(sql, ofType<RowMapper<*>>(), 3) } returns list
+		every { template.query(sql, ofType<RowMapper<Int>>(), 3) } returns list
 		assertThat(template.query(sql, 3) { rs, _ ->
 			rs.getInt(1)
 		}).isEqualTo(list)
-		verify { template.query(sql, ofType<RowMapper<*>>(), 3) }
+		verify { template.query(sql, ofType<RowMapper<Int>>(), 3) }
+	}
+
+	@Test
+	fun `query with nullable RowMapper-like function`() {
+		val list = mutableListOf(1, null, 3)
+		every { template.query(sql, ofType<RowMapper<Int?>>(), 3) } returns list
+		assertThat(template.query(sql, 3) { rs, _ ->
+			rs.getInt(1)
+		}).isEqualTo(list)
+		verify { template.query(sql, ofType<RowMapper<Int?>>(), 3) }
 	}
 
 }

spring-tx/src/main/java/org/springframework/dao/support/DataAccessUtils.java

@@ -22,6 +22,7 @@ import java.util.List;
 import java.util.Optional;
 import java.util.stream.Stream;
 
+import org.jspecify.annotations.NonNull;
 import org.jspecify.annotations.Nullable;
 
 import org.springframework.dao.DataAccessException;
@@ -115,7 +116,7 @@ public abstract class DataAccessUtils {
 	 * element has been found in the given Collection
 	 * @since 6.1
 	 */
-	public static <T> Optional<T> optionalResult(@Nullable Collection<T> results) throws IncorrectResultSizeDataAccessException {
+	public static <T extends @Nullable Object> Optional<@NonNull T> optionalResult(@Nullable Collection<T> results) throws IncorrectResultSizeDataAccessException {
 		return Optional.ofNullable(singleResult(results));
 	}
 
@@ -158,7 +159,7 @@ public abstract class DataAccessUtils {
 	 * @throws EmptyResultDataAccessException if no element at all
 	 * has been found in the given Collection
 	 */
-	public static <T> T requiredSingleResult(@Nullable Collection<T> results) throws IncorrectResultSizeDataAccessException {
+	public static <T extends @Nullable Object> @NonNull T requiredSingleResult(@Nullable Collection<T> results) throws IncorrectResultSizeDataAccessException {
 		if (CollectionUtils.isEmpty(results)) {
 			throw new EmptyResultDataAccessException(1);
 		}
@@ -184,7 +185,7 @@ public abstract class DataAccessUtils {
 	 * has been found in the given Collection
 	 * @since 5.0.2
 	 */
-	public static <T> @Nullable T nullableSingleResult(@Nullable Collection<T> results) throws IncorrectResultSizeDataAccessException {
+	public static <T extends @Nullable Object> T nullableSingleResult(@Nullable Collection<T> results) throws IncorrectResultSizeDataAccessException {
 		// This is identical to the requiredSingleResult implementation but differs in the
 		// semantics of the incoming Collection (which we currently can't formally express)
 		if (CollectionUtils.isEmpty(results)) {