Fix overridden methods nullability

Issue: SPR-15869

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

@@ -147,6 +147,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if there is any problem executing the query
 	 * @see #queryForObject(String, Object[], RowMapper)
 	 */
+	@Nullable
 	<T> T queryForObject(String sql, RowMapper<T> rowMapper) throws DataAccessException;
 
 	/**
@@ -531,6 +532,7 @@ public interface JdbcOperations {
 	 * return exactly one row
 	 * @throws DataAccessException if the query fails
 	 */
+	@Nullable
 	<T> T queryForObject(String sql, Object[] args, int[] argTypes, RowMapper<T> rowMapper)
 			throws DataAccessException;
 
@@ -549,6 +551,7 @@ public interface JdbcOperations {
 	 * return exactly one row
 	 * @throws DataAccessException if the query fails
 	 */
+	@Nullable
 	<T> T queryForObject(String sql, Object[] args, RowMapper<T> rowMapper) throws DataAccessException;
 
 	/**
@@ -566,6 +569,7 @@ public interface JdbcOperations {
 	 * return exactly one row
 	 * @throws DataAccessException if the query fails
 	 */
+	@Nullable
 	<T> T queryForObject(String sql, RowMapper<T> rowMapper, @Nullable Object... args) throws DataAccessException;
 
 	/**

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

@@ -316,6 +316,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	//-------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public <T> T execute(ConnectionCallback<T> action) throws DataAccessException {
 		Assert.notNull(action, "Callback object must not be null");
 
@@ -361,6 +362,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	//-------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public <T> T execute(StatementCallback<T> action) throws DataAccessException {
 		Assert.notNull(action, "Callback object must not be null");
 
@@ -395,6 +397,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 		}
 		class ExecuteStatementCallback implements StatementCallback<Object>, SqlProvider {
 			@Override
+			@Nullable
 			public Object doInStatement(Statement stmt) throws SQLException {
 				stmt.execute(sql);
 				return null;
@@ -408,6 +411,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(final String sql, final ResultSetExtractor<T> rse) throws DataAccessException {
 		Assert.notNull(sql, "SQL must not be null");
 		Assert.notNull(rse, "ResultSetExtractor must not be null");
@@ -416,6 +420,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 		}
 		class QueryStatementCallback implements StatementCallback<T>, SqlProvider {
 			@Override
+			@Nullable
 			public T doInStatement(Statement stmt) throws SQLException {
 				ResultSet rs = null;
 				try {
@@ -452,12 +457,14 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, RowMapper<T> rowMapper) throws DataAccessException {
 		List<T> results = query(sql, rowMapper);
 		return DataAccessUtils.requiredSingleResult(results);
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, Class<T> requiredType) throws DataAccessException {
 		return queryForObject(sql, getSingleColumnRowMapper(requiredType));
 	}
@@ -561,6 +568,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 			}
 
 			@Override
+			@Nullable
 			public String getSql() {
 				return this.currSql;
 			}
@@ -577,6 +585,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	//-------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public <T> T execute(PreparedStatementCreator psc, PreparedStatementCallback<T> action)
 			throws DataAccessException {
 
@@ -619,6 +628,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T execute(String sql, PreparedStatementCallback<T> action) throws DataAccessException {
 		return execute(new SimplePreparedStatementCreator(sql), action);
 	}
@@ -645,6 +655,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 
 		return execute(psc, new PreparedStatementCallback<T>() {
 			@Override
+			@Nullable
 			public T doInPreparedStatement(PreparedStatement ps) throws SQLException {
 				ResultSet rs = null;
 				try {
@@ -665,26 +676,31 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(PreparedStatementCreator psc, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(psc, null, rse);
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(String sql, @Nullable PreparedStatementSetter pss, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(new SimplePreparedStatementCreator(sql), pss, rse);
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(String sql, Object[] args, int[] argTypes, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(sql, newArgTypePreparedStatementSetter(args, argTypes), rse);
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(String sql, @Nullable Object[] args, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(sql, newArgPreparedStatementSetter(args), rse);
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(String sql, ResultSetExtractor<T> rse, @Nullable Object... args) throws DataAccessException {
 		return query(sql, newArgPreparedStatementSetter(args), rse);
 	}
@@ -740,6 +756,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, Object[] args, int[] argTypes, RowMapper<T> rowMapper)
 			throws DataAccessException {
 
@@ -748,18 +765,21 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, @Nullable Object[] args, RowMapper<T> rowMapper) throws DataAccessException {
 		List<T> results = query(sql, args, new RowMapperResultSetExtractor<>(rowMapper, 1));
 		return DataAccessUtils.requiredSingleResult(results);
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, RowMapper<T> rowMapper, @Nullable Object... args) throws DataAccessException {
 		List<T> results = query(sql, args, new RowMapperResultSetExtractor<>(rowMapper, 1));
 		return DataAccessUtils.requiredSingleResult(results);
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, Object[] args, int[] argTypes, Class<T> requiredType)
 			throws DataAccessException {
 
@@ -1010,6 +1030,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	//-------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public <T> T execute(CallableStatementCreator csc, CallableStatementCallback<T> action)
 			throws DataAccessException {
 
@@ -1052,6 +1073,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T execute(String callString, CallableStatementCallback<T> action) throws DataAccessException {
 		return execute(new SimpleCallableStatementCreator(callString), action);
 	}
@@ -1523,6 +1545,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 		}
 
 		@Override
+		@Nullable
 		public Object extractData(ResultSet rs) throws SQLException {
 			while (rs.next()) {
 				this.rch.processRow(rs);

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

@@ -20,8 +20,6 @@ import java.sql.Connection;
 import java.sql.SQLException;
 import java.util.Map;
 
-import org.springframework.lang.Nullable;
-
 /**
  * Implement this interface when parameters need to be customized based
  * on the connection. We might need to do this to make use of proprietary
@@ -45,7 +43,6 @@ public interface ParameterMapper {
 	 * parameter values (that is, there's no need to catch SQLException)
 	 * @return Map of input parameters, keyed by name (never {@code null})
 	 */
-	@Nullable
 	Map<String, ?> createMap(Connection con) throws SQLException;
 
 }

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

@@ -86,6 +86,7 @@ public class SingleColumnRowMapper<T> implements RowMapper<T> {
 	 */
 	@Override
 	@SuppressWarnings("unchecked")
+	@Nullable
 	public T mapRow(ResultSet rs, int rowNum) throws SQLException {
 		// Validate column count.
 		ResultSetMetaData rsmd = rs.getMetaData();

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/Db2CallMetaDataProvider.java

@@ -65,6 +65,7 @@ public class Db2CallMetaDataProvider extends GenericCallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String metaDataSchemaNameToUse(@Nullable String schemaName) {
 		if (schemaName != null) {
 			return super.metaDataSchemaNameToUse(schemaName);

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/DerbyCallMetaDataProvider.java

@@ -36,6 +36,7 @@ public class DerbyCallMetaDataProvider extends GenericCallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String metaDataSchemaNameToUse(@Nullable String schemaName) {
 		if (schemaName != null) {
 			return super.metaDataSchemaNameToUse(schemaName);

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/GenericCallMetaDataProvider.java

@@ -119,6 +119,7 @@ public class GenericCallMetaDataProvider implements CallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String procedureNameToUse(@Nullable String procedureName) {
 		if (procedureName == null) {
 			return null;
@@ -135,6 +136,7 @@ public class GenericCallMetaDataProvider implements CallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String catalogNameToUse(@Nullable String catalogName) {
 		if (catalogName == null) {
 			return null;
@@ -151,6 +153,7 @@ public class GenericCallMetaDataProvider implements CallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String schemaNameToUse(@Nullable String schemaName) {
 		if (schemaName == null) {
 			return null;
@@ -167,6 +170,7 @@ public class GenericCallMetaDataProvider implements CallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String metaDataCatalogNameToUse(@Nullable String catalogName) {
 		if (isSupportsCatalogsInProcedureCalls()) {
 			return catalogNameToUse(catalogName);
@@ -177,6 +181,7 @@ public class GenericCallMetaDataProvider implements CallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String metaDataSchemaNameToUse(@Nullable String schemaName) {
 		if (isSupportsSchemasInProcedureCalls()) {
 			return schemaNameToUse(schemaName);
@@ -187,6 +192,7 @@ public class GenericCallMetaDataProvider implements CallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String parameterNameToUse(@Nullable String parameterName) {
 		if (parameterName == null) {
 			return null;

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/GenericTableMetaDataProvider.java

@@ -124,6 +124,7 @@ public class GenericTableMetaDataProvider implements TableMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String getSimpleQueryForGetGeneratedKey(String tableName, String keyColumnName) {
 		return null;
 	}
@@ -222,6 +223,7 @@ public class GenericTableMetaDataProvider implements TableMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String tableNameToUse(@Nullable String tableName) {
 		if (tableName == null) {
 			return null;
@@ -238,6 +240,7 @@ public class GenericTableMetaDataProvider implements TableMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String catalogNameToUse(@Nullable String catalogName) {
 		if (catalogName == null) {
 			return null;
@@ -254,6 +257,7 @@ public class GenericTableMetaDataProvider implements TableMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String schemaNameToUse(@Nullable String schemaName) {
 		if (schemaName == null) {
 			return null;
@@ -270,11 +274,13 @@ public class GenericTableMetaDataProvider implements TableMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String metaDataCatalogNameToUse(@Nullable String catalogName) {
 		return catalogNameToUse(catalogName);
 	}
 
 	@Override
+	@Nullable
 	public String metaDataSchemaNameToUse(@Nullable String schemaName) {
 		if (schemaName == null) {
 			return schemaNameToUse(getDefaultSchema());

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/OracleCallMetaDataProvider.java

@@ -58,12 +58,14 @@ public class OracleCallMetaDataProvider extends GenericCallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String metaDataCatalogNameToUse(@Nullable String catalogName) {
 		// Oracle uses catalog name for package name or an empty string if no package
 		return (catalogName == null ? "" : catalogNameToUse(catalogName));
 	}
 
 	@Override
+	@Nullable
 	public String metaDataSchemaNameToUse(@Nullable String schemaName) {
 		// Use current user schema if no schema specified
 		return (schemaName == null ? getUserName() : super.metaDataSchemaNameToUse(schemaName));

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/OracleTableMetaDataProvider.java

@@ -95,6 +95,7 @@ public class OracleTableMetaDataProvider extends GenericTableMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	protected String getDefaultSchema() {
 		if (this.defaultSchema != null) {
 			return defaultSchema;

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/PostgresCallMetaDataProvider.java

@@ -58,6 +58,7 @@ public class PostgresCallMetaDataProvider extends GenericCallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String metaDataSchemaNameToUse(@Nullable String schemaName) {
 		// Use public schema if no schema specified
 		return (schemaName == null ? "public" : super.metaDataSchemaNameToUse(schemaName));

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/SqlServerCallMetaDataProvider.java

@@ -41,6 +41,7 @@ public class SqlServerCallMetaDataProvider extends GenericCallMetaDataProvider {
 
 
 	@Override
+	@Nullable
 	public String parameterNameToUse(@Nullable String parameterName) {
 		if (parameterName == null) {
 			return null;

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/SybaseCallMetaDataProvider.java

@@ -41,6 +41,7 @@ public class SybaseCallMetaDataProvider extends GenericCallMetaDataProvider {
 
 
 	@Override
+	@Nullable
 	public String parameterNameToUse(@Nullable String parameterName) {
 		if (parameterName == null) {
 			return null;

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

@@ -19,6 +19,7 @@ package org.springframework.jdbc.core.namedparam;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -74,6 +75,7 @@ public abstract class AbstractSqlParameterSource implements SqlParameterSource {
 	 * or {@code null} if not registered
 	 */
 	@Override
+	@Nullable
 	public String getTypeName(String paramName) {
 		Assert.notNull(paramName, "Parameter name must not be null");
 		return this.typeNames.get(paramName);

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

@@ -63,6 +63,7 @@ public class BeanPropertySqlParameterSource extends AbstractSqlParameterSource {
 	}
 
 	@Override
+	@Nullable
 	public Object getValue(String paramName) throws IllegalArgumentException {
 		try {
 			return this.beanWrapper.getPropertyValue(paramName);

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

@@ -16,6 +16,8 @@
 
 package org.springframework.jdbc.core.namedparam;
 
+import org.springframework.lang.Nullable;
+
 /**
  * A simple empty implementation of the {@link SqlParameterSource} interface.
  *
@@ -36,6 +38,7 @@ public class EmptySqlParameterSource implements SqlParameterSource {
 	}
 
 	@Override
+	@Nullable
 	public Object getValue(String paramName) throws IllegalArgumentException {
 		throw new IllegalArgumentException("This SqlParameterSource is empty");
 	}
@@ -46,6 +49,7 @@ public class EmptySqlParameterSource implements SqlParameterSource {
 	}
 
 	@Override
+	@Nullable
 	public String getTypeName(String paramName) {
 		return null;
 	}

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

@@ -155,6 +155,7 @@ public class MapSqlParameterSource extends AbstractSqlParameterSource {
 	}
 
 	@Override
+	@Nullable
 	public Object getValue(String paramName) {
 		if (!hasValue(paramName)) {
 			throw new IllegalArgumentException("No value registered for key '" + paramName + "'");

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

@@ -239,6 +239,7 @@ public interface NamedParameterJdbcOperations {
 	 * one column in that row
 	 * @throws org.springframework.dao.DataAccessException if the query fails
 	 */
+	@Nullable
 	<T> T queryForObject(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
 			throws DataAccessException;
 
@@ -256,6 +257,7 @@ public interface NamedParameterJdbcOperations {
 	 * one column in that row
 	 * @throws org.springframework.dao.DataAccessException if the query fails
 	 */
+	@Nullable
 	<T> T queryForObject(String sql, Map<String, ?> paramMap, RowMapper<T> rowMapper)
 			throws DataAccessException;
 

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

@@ -130,6 +130,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 
 
 	@Override
+	@Nullable
 	public <T> T execute(String sql, SqlParameterSource paramSource, PreparedStatementCallback<T> action)
 			throws DataAccessException {
 
@@ -137,6 +138,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T execute(String sql, Map<String, ?> paramMap, PreparedStatementCallback<T> action)
 			throws DataAccessException {
 
@@ -144,11 +146,13 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T execute(String sql, PreparedStatementCallback<T> action) throws DataAccessException {
 		return execute(sql, EmptySqlParameterSource.INSTANCE, action);
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(String sql, SqlParameterSource paramSource, ResultSetExtractor<T> rse)
 			throws DataAccessException {
 
@@ -156,6 +160,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(String sql, Map<String, ?> paramMap, ResultSetExtractor<T> rse)
 			throws DataAccessException {
 
@@ -163,6 +168,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(String sql, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(sql, EmptySqlParameterSource.INSTANCE, rse);
 	}
@@ -206,6 +212,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
 			throws DataAccessException {
 
@@ -214,6 +221,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, Map<String, ?> paramMap, RowMapper<T>rowMapper)
 			throws DataAccessException {
 
@@ -221,6 +229,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, SqlParameterSource paramSource, Class<T> requiredType)
 			throws DataAccessException {
 
@@ -228,6 +237,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, Map<String, ?> paramMap, Class<T> requiredType)
 			throws DataAccessException {
 

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

@@ -25,6 +25,7 @@ import org.springframework.dao.EmptyResultDataAccessException;
 import org.springframework.dao.IncorrectResultSizeDataAccessException;
 import org.springframework.jdbc.LobRetrievalFailureException;
 import org.springframework.jdbc.core.ResultSetExtractor;
+import org.springframework.lang.Nullable;
 
 /**
  * Abstract ResultSetExtractor implementation that assumes streaming of LOB data.
@@ -65,6 +66,7 @@ public abstract class AbstractLobStreamingResultSetExtractor<T> implements Resul
 	 * @see org.springframework.jdbc.LobRetrievalFailureException
 	 */
 	@Override
+	@Nullable
 	public final T extractData(ResultSet rs) throws SQLException, DataAccessException {
 		if (!rs.next()) {
 			handleNoRowFound();

spring-jdbc/src/main/java/org/springframework/jdbc/datasource/embedded/EmbeddedDatabaseFactoryBean.java

@@ -66,6 +66,7 @@ public class EmbeddedDatabaseFactoryBean extends EmbeddedDatabaseFactory
 
 
 	@Override
+	@Nullable
 	public DataSource getObject() {
 		return getDataSource();
 	}

spring-jdbc/src/main/java/org/springframework/jdbc/datasource/lookup/IsolationLevelDataSourceRouter.java

@@ -17,6 +17,7 @@
 package org.springframework.jdbc.datasource.lookup;
 
 import org.springframework.core.Constants;
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.TransactionDefinition;
 import org.springframework.transaction.support.DefaultTransactionDefinition;
 import org.springframework.transaction.support.TransactionSynchronizationManager;
@@ -119,6 +120,7 @@ public class IsolationLevelDataSourceRouter extends AbstractRoutingDataSource {
 	}
 
 	@Override
+	@Nullable
 	protected Object determineCurrentLookupKey() {
 		return TransactionSynchronizationManager.getCurrentTransactionIsolationLevel();
 	}

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

@@ -61,6 +61,7 @@ public abstract class MappingSqlQuery<T> extends MappingSqlQueryWithParameters<T
 	 * @see #mapRow(ResultSet, int)
 	 */
 	@Override
+	@Nullable
 	protected final T mapRow(ResultSet rs, int rowNum, @Nullable Object[] parameters, @Nullable Map<?, ?> context)
 			throws SQLException {
 

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

@@ -117,6 +117,7 @@ public abstract class MappingSqlQueryWithParameters<T> extends SqlQuery<T> {
 		}
 
 		@Override
+		@Nullable
 		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

@@ -127,6 +127,7 @@ public class SqlFunction<T> extends MappingSqlQuery<T> {
 	 * of rows returned, this is treated as an error.
 	 */
 	@Override
+	@Nullable
 	protected T mapRow(ResultSet rs, int rowNum) throws SQLException {
 		return this.rowMapper.mapRow(rs, rowNum);
 	}

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

@@ -64,6 +64,7 @@ public abstract class AbstractFallbackSQLExceptionTranslator implements SQLExcep
 	 * {@link #getFallbackTranslator() fallback translator} if necessary.
 	 */
 	@Override
+	@Nullable
 	public DataAccessException translate(@Nullable String task, @Nullable String sql, SQLException ex) {
 		Assert.notNull(ex, "Cannot translate a null SQLException");
 		if (task == null) {

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

@@ -23,6 +23,7 @@ import java.util.Map;
 
 import org.springframework.dao.DataRetrievalFailureException;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
+import org.springframework.lang.Nullable;
 
 /**
  * Default implementation of the {@link KeyHolder} interface, to be used for
@@ -58,6 +59,7 @@ public class GeneratedKeyHolder implements KeyHolder {
 
 
 	@Override
+	@Nullable
 	public Number getKey() throws InvalidDataAccessApiUsageException, DataRetrievalFailureException {
 		if (this.keyList.size() == 0) {
 			return null;
@@ -85,6 +87,7 @@ public class GeneratedKeyHolder implements KeyHolder {
 	}
 
 	@Override
+	@Nullable
 	public Map<String, Object> getKeys() throws InvalidDataAccessApiUsageException {
 		if (this.keyList.size() == 0) {
 			return null;

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

@@ -168,6 +168,7 @@ public class SQLErrorCodeSQLExceptionTranslator extends AbstractFallbackSQLExcep
 
 
 	@Override
+	@Nullable
 	protected DataAccessException doTranslate(String task, String sql, SQLException ex) {
 		SQLException sqlEx = ex;
 		if (sqlEx instanceof BatchUpdateException && sqlEx.getNextException() != null) {

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

@@ -88,6 +88,7 @@ public class SQLStateSQLExceptionTranslator extends AbstractFallbackSQLException
 
 
 	@Override
+	@Nullable
 	protected DataAccessException doTranslate(String task, String sql, SQLException ex) {
 		// First, the getSQLState check...
 		String sqlState = getSqlState(ex);

spring-jdbc/src/main/java/org/springframework/jdbc/support/lob/AbstractLobHandler.java

@@ -21,6 +21,8 @@ import java.io.Reader;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 
+import org.springframework.lang.Nullable;
+
 /**
  * Abstract base class for {@link LobHandler} implementations.
  *
@@ -34,21 +36,25 @@ import java.sql.SQLException;
 public abstract class AbstractLobHandler implements LobHandler {
 
 	@Override
+	@Nullable
 	public byte[] getBlobAsBytes(ResultSet rs, String columnName) throws SQLException {
 		return getBlobAsBytes(rs, rs.findColumn(columnName));
 	}
 
 	@Override
+	@Nullable
 	public InputStream getBlobAsBinaryStream(ResultSet rs, String columnName) throws SQLException {
 		return getBlobAsBinaryStream(rs, rs.findColumn(columnName));
 	}
 
 	@Override
+	@Nullable
 	public String getClobAsString(ResultSet rs, String columnName) throws SQLException {
 		return getClobAsString(rs, rs.findColumn(columnName));
 	}
 
 	@Override
+	@Nullable
 	public InputStream getClobAsAsciiStream(ResultSet rs, String columnName) throws SQLException {
 		return getClobAsAsciiStream(rs, rs.findColumn(columnName));
 	}

spring-jdbc/src/main/java/org/springframework/jdbc/support/lob/DefaultLobHandler.java

@@ -148,6 +148,7 @@ public class DefaultLobHandler extends AbstractLobHandler {
 
 
 	@Override
+	@Nullable
 	public byte[] getBlobAsBytes(ResultSet rs, int columnIndex) throws SQLException {
 		logger.debug("Returning BLOB as bytes");
 		if (this.wrapAsLob) {
@@ -160,6 +161,7 @@ public class DefaultLobHandler extends AbstractLobHandler {
 	}
 
 	@Override
+	@Nullable
 	public InputStream getBlobAsBinaryStream(ResultSet rs, int columnIndex) throws SQLException {
 		logger.debug("Returning BLOB as binary stream");
 		if (this.wrapAsLob) {
@@ -172,6 +174,7 @@ public class DefaultLobHandler extends AbstractLobHandler {
 	}
 
 	@Override
+	@Nullable
 	public String getClobAsString(ResultSet rs, int columnIndex) throws SQLException {
 		logger.debug("Returning CLOB as string");
 		if (this.wrapAsLob) {

spring-jdbc/src/main/java/org/springframework/jdbc/support/xml/Jdbc4SqlXmlHandler.java

@@ -53,42 +53,49 @@ public class Jdbc4SqlXmlHandler implements SqlXmlHandler {
 	//-------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public String getXmlAsString(ResultSet rs, String columnName) throws SQLException {
 		SQLXML xmlObject = rs.getSQLXML(columnName);
 		return (xmlObject != null ? xmlObject.getString() : null);
 	}
 
 	@Override
+	@Nullable
 	public String getXmlAsString(ResultSet rs, int columnIndex) throws SQLException {
 		SQLXML xmlObject = rs.getSQLXML(columnIndex);
 		return (xmlObject != null ? xmlObject.getString() : null);
 	}
 
 	@Override
+	@Nullable
 	public InputStream getXmlAsBinaryStream(ResultSet rs, String columnName) throws SQLException {
 		SQLXML xmlObject = rs.getSQLXML(columnName);
 		return (xmlObject != null ? xmlObject.getBinaryStream() : null);
 	}
 
 	@Override
+	@Nullable
 	public InputStream getXmlAsBinaryStream(ResultSet rs, int columnIndex) throws SQLException {
 		SQLXML xmlObject = rs.getSQLXML(columnIndex);
 		return (xmlObject != null ? xmlObject.getBinaryStream() : null);
 	}
 
 	@Override
+	@Nullable
 	public Reader getXmlAsCharacterStream(ResultSet rs, String columnName) throws SQLException {
 		SQLXML xmlObject = rs.getSQLXML(columnName);
 		return (xmlObject != null ? xmlObject.getCharacterStream() : null);
 	}
 
 	@Override
+	@Nullable
 	public Reader getXmlAsCharacterStream(ResultSet rs, int columnIndex) throws SQLException {
 		SQLXML xmlObject = rs.getSQLXML(columnIndex);
 		return (xmlObject != null ? xmlObject.getCharacterStream() : null);
 	}
 
 	@Override
+	@Nullable
 	public Source getXmlAsSource(ResultSet rs, String columnName, @Nullable Class<? extends Source> sourceClass)
 			throws SQLException {
 
@@ -100,6 +107,7 @@ public class Jdbc4SqlXmlHandler implements SqlXmlHandler {
 	}
 
 	@Override
+	@Nullable
 	public Source getXmlAsSource(ResultSet rs, int columnIndex, @Nullable Class<? extends Source> sourceClass)
 			throws SQLException {