DATAJDBC-235 - Polishing.

Corrected nullability annotations.
Minor improvements in Javadoc.
Added @author tags.
Removed unused imports.

src/main/java/org/springframework/data/jdbc/mybatis/MyBatisDataAccessStrategy.java

@@ -22,7 +22,6 @@ import java.util.Map;
 
 import org.apache.ibatis.session.SqlSession;
 import org.mybatis.spring.SqlSessionTemplate;
-import org.springframework.data.convert.EntityInstantiators;
 import org.springframework.data.jdbc.core.CascadingDataAccessStrategy;
 import org.springframework.data.jdbc.core.DataAccessStrategy;
 import org.springframework.data.jdbc.core.DefaultDataAccessStrategy;
@@ -60,10 +59,8 @@ public class MyBatisDataAccessStrategy implements DataAccessStrategy {
 	 * uses a {@link DefaultDataAccessStrategy}
 	 */
 	public static DataAccessStrategy createCombinedAccessStrategy(RelationalMappingContext context,
-			RelationalConverter converter,
-			NamedParameterJdbcOperations operations, SqlSession sqlSession) {
-		return createCombinedAccessStrategy(context, converter, operations, sqlSession,
-				NamespaceStrategy.DEFAULT_INSTANCE);
+			RelationalConverter converter, NamedParameterJdbcOperations operations, SqlSession sqlSession) {
+		return createCombinedAccessStrategy(context, converter, operations, sqlSession, NamespaceStrategy.DEFAULT_INSTANCE);
 	}
 
 	/**
@@ -105,7 +102,7 @@ public class MyBatisDataAccessStrategy implements DataAccessStrategy {
 	 * transaction. Note that the resulting {@link DataAccessStrategy} only handles MyBatis. It does not include the
 	 * functionality of the {@link org.springframework.data.jdbc.core.DefaultDataAccessStrategy} which one normally still
 	 * wants. Use
-	 * {@link #createCombinedAccessStrategy(RelationalMappingContext, EntityInstantiators, NamedParameterJdbcOperations, SqlSession, NamespaceStrategy)}
+	 * {@link #createCombinedAccessStrategy(RelationalMappingContext, RelationalConverter, NamedParameterJdbcOperations, SqlSession, NamespaceStrategy)}
 	 * to create such a {@link DataAccessStrategy}.
 	 *
 	 * @param sqlSession Must be non {@literal null}.

src/main/java/org/springframework/data/jdbc/repository/config/JdbcConfiguration.java

@@ -57,7 +57,8 @@ public class JdbcConfiguration {
 
 	/**
 	 * Register custom {@link Converter}s in a {@link CustomConversions} object if required. These
-	 * {@link CustomConversions} will be registered with the {@link #jdbcMappingContext()}. Returns an empty
+	 * {@link CustomConversions} will be registered with the
+	 * {@link #relationalConverter(RelationalMappingContext, CustomConversions)}. Returns an empty
 	 * {@link JdbcCustomConversions} instance by default.
 	 *
 	 * @return must not be {@literal null}.

src/main/java/org/springframework/data/jdbc/repository/support/JdbcQueryLookupStrategy.java

@@ -39,6 +39,7 @@ import org.springframework.util.Assert;
  * @author Jens Schauder
  * @author Kazuki Shimizu
  * @author Oliver Gierke
+ * @author Mark Paluch
  * @since 1.0
  */
 class JdbcQueryLookupStrategy implements QueryLookupStrategy {

src/main/java/org/springframework/data/jdbc/repository/support/JdbcRepositoryFactoryBean.java

@@ -40,6 +40,7 @@ import org.springframework.util.Assert;
  * @author Greg Turnquist
  * @author Christoph Strobl
  * @author Oliver Gierke
+ * @author Mark Paluch
  * @since 1.0
  */
 public class JdbcRepositoryFactoryBean<T extends Repository<S, ID>, S, ID extends Serializable> //

src/main/java/org/springframework/data/relational/core/conversion/BasicRelationalConverter.java

@@ -192,9 +192,10 @@ public class BasicRelationalConverter implements RelationalConverter {
 	 * Checks whether we have a custom conversion registered for the given value into an arbitrary simple JDBC type.
 	 * Returns the converted value if so. If not, we perform special enum handling or simply return the value as is.
 	 *
-	 * @param value
-	 * @return
+	 * @param value to be converted. Must not be {@code null}.
+	 * @return the converted value if a conversion applies or the original value. Might return {@code null}.
 	 */
+	@Nullable
 	private Object getPotentiallyConvertedSimpleWrite(Object value) {
 
 		Optional<Class<?>> customTarget = conversions.getCustomWriteTarget(value.getClass());
@@ -210,9 +211,9 @@ public class BasicRelationalConverter implements RelationalConverter {
 	 * Checks whether we have a custom conversion for the given simple object. Converts the given value if so, applies
 	 * {@link Enum} handling or returns the value as is.
 	 *
-	 * @param value
-	 * @param target must not be {@literal null}.
-	 * @return
+	 * @param value to be converted. May be {@code null}..
+	 * @param target May be {@code null}..
+	 * @return the converted value if a conversion applies or the original value. Might return {@code null}.
 	 */
 	@Nullable
 	@SuppressWarnings({ "rawtypes", "unchecked" })

src/main/java/org/springframework/data/relational/core/conversion/RelationalConverter.java

@@ -33,6 +33,7 @@ import org.springframework.lang.Nullable;
  * vice versa.
  *
  * @author Mark Paluch
+ * @author Jens Schauder
  */
 public interface RelationalConverter {
 
@@ -54,10 +55,10 @@ public interface RelationalConverter {
 	 * Create a new instance of {@link PersistentEntity} given {@link ParameterValueProvider} to obtain constructor
 	 * properties.
 	 *
-	 * @param entity
-	 * @param parameterValueProvider
-	 * @param <T>
-	 * @return
+	 * @param entity the kind of entity to create. Must not be {@code null}.
+	 * @param parameterValueProvider a function that provides the value to pass to a constructor, given a {@link Parameter}. Must not be {@code null}.
+	 * @param <T> the type of entity to create.
+	 * @return the instantiated entity. Guaranteed to be not {@code null}.
 	 */
 	<T> T createInstance(PersistentEntity<T, RelationalPersistentProperty> entity,
 			Function<Parameter<?, RelationalPersistentProperty>, Object> parameterValueProvider);
@@ -65,18 +66,18 @@ public interface RelationalConverter {
 	/**
 	 * Return a {@link PersistentPropertyAccessor} to access property values of the {@code instance}.
 	 *
-	 * @param persistentEntity
-	 * @param instance
-	 * @return
+	 * @param persistentEntity the kind of entity to operate on. Must not be {@code null}.
+	 * @param instance the instance to operate on. Must not be {@code null}.
+	 * @return Guaranteed to be not {@code null}.
 	 */
 	<T> PersistentPropertyAccessor<T> getPropertyAccessor(PersistentEntity<T, ?> persistentEntity, T instance);
 
 	/**
 	 * Read a relational value into the desired {@link TypeInformation destination type}.
 	 *
-	 * @param value
-	 * @param type
-	 * @return
+	 * @param value a value as it is returned by the driver accessing the persistence store. May be {@code null}.
+	 * @param type {@link TypeInformation} into which the value is to be converted. Must not be {@code null}.
+	 * @return The converted value. May be {@code null}.
 	 */
 	@Nullable
 	Object readValue(@Nullable Object value, TypeInformation<?> type);
@@ -84,9 +85,9 @@ public interface RelationalConverter {
 	/**
 	 * Write a property value into a relational type that can be stored natively.
 	 *
-	 * @param value
-	 * @param type
-	 * @return
+	 * @param value a value as it is used in the object model. May be {@code null}.
+	 * @param type {@link TypeInformation} into which the value is to be converted. Must not be {@code null}.
+	 * @return The converted value. May be {@code null}.
 	 */
 	@Nullable
 	Object writeValue(@Nullable Object value, TypeInformation<?> type);

src/main/java/org/springframework/data/relational/core/mapping/RelationalMappingContext.java

@@ -55,7 +55,6 @@ public class RelationalMappingContext extends AbstractMappingContext<RelationalP
 	 * Creates a new {@link RelationalMappingContext} using the given {@link NamingStrategy}.
 	 *
 	 * @param namingStrategy must not be {@literal null}.
-	 * @param customizer must not be {@literal null}.
 	 */
 	public RelationalMappingContext(NamingStrategy namingStrategy) {