Polishing.

Pattern matching usage.
Diamond operator usage.
Remove unused import.
isEmpty usage.

Original pull request #1912

Author: ngocnhan-tran1996

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/core/convert/IterableOfEntryToMapConverter.java

@@ -41,12 +41,12 @@ class IterableOfEntryToMapConverter implements ConditionalConverter, Converter<I
 
 		source.forEach(element -> {
 
-			if (!(element instanceof Entry)) {
-				throw new IllegalArgumentException(String.format("Cannot convert %s to Map.Entry", element.getClass()));
+			if (element instanceof Entry entry) {
+				result.put(entry.getKey(), entry.getValue());
+				return;
 			}
 
-			Entry entry = (Entry) element;
-			result.put(entry.getKey(), entry.getValue());
+			throw new IllegalArgumentException(String.format("Cannot convert %s to Map.Entry", element.getClass()));
 		});
 
 		return result;

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/core/convert/JdbcColumnTypes.java

@@ -20,7 +20,6 @@
 import java.time.OffsetDateTime;
 import java.time.ZonedDateTime;
 import java.time.temporal.Temporal;
-import java.util.Date;
 import java.util.LinkedHashMap;
 import java.util.Map;
 

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/core/convert/QueryMapper.java

@@ -315,7 +315,7 @@ private Condition mapCondition(CriteriaDefinition criteria, MapSqlParameterSourc
 				&& metadataBackedField.property != null //
 				&& (criteria.getValue() == null || !criteria.getValue().getClass().isArray())) {
 
-			RelationalPersistentProperty property = ((MetadataBackedField) propertyField).property;
+			RelationalPersistentProperty property = metadataBackedField.property;
 			JdbcValue jdbcValue = convertToJdbcValue(property, criteria.getValue());
 			mappedValue = jdbcValue.getValue();
 			sqlType = jdbcValue.getJdbcType() != null ? jdbcValue.getJdbcType() : propertyField.getSqlType();

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/core/mapping/BasicJdbcPersistentProperty.java

@@ -20,7 +20,6 @@
 import org.springframework.data.mapping.model.SimpleTypeHolder;
 import org.springframework.data.relational.core.mapping.BasicRelationalPersistentProperty;
 import org.springframework.data.relational.core.mapping.NamingStrategy;
-import org.springframework.data.relational.core.mapping.RelationalMappingContext;
 import org.springframework.data.relational.core.mapping.RelationalPersistentProperty;
 
 /**

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/core/mapping/JdbcMappingContext.java

@@ -15,8 +15,6 @@
  */
 package org.springframework.data.jdbc.core.mapping;
 
-import org.springframework.data.mapping.InstanceCreatorMetadata;
-import org.springframework.data.mapping.Parameter;
 import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.mapping.model.Property;
 import org.springframework.data.mapping.model.SimpleTypeHolder;
@@ -25,8 +23,6 @@
 import org.springframework.data.relational.core.mapping.RelationalPersistentEntity;
 import org.springframework.data.relational.core.mapping.RelationalPersistentProperty;
 import org.springframework.data.util.TypeInformation;
-import org.springframework.util.Assert;
-import org.springframework.util.StringUtils;
 
 /**
  * {@link MappingContext} implementation for JDBC.

spring-data-r2dbc/src/main/java/org/springframework/data/r2dbc/core/DefaultStatementMapper.java

@@ -172,8 +172,7 @@ private PreparedOperation<Insert> getMappedObject(InsertSpec insertSpec,
 
 		for (Assignment assignment : boundAssignments.getAssignments()) {
 
-			if (assignment instanceof AssignValue) {
-				AssignValue assignValue = (AssignValue) assignment;
+			if (assignment instanceof AssignValue assignValue) {
 
 				insertBuilder.column(assignValue.getColumn());
 				withBuild = insertBuilder.value(assignValue.getValue());

spring-data-r2dbc/src/main/java/org/springframework/data/r2dbc/core/NamedParameterExpander.java

@@ -54,7 +54,7 @@ class NamedParameterExpander {
 	/**
 	 * Cache of original SQL String to ParsedSql representation.
 	 */
-	@SuppressWarnings("serial") private final Map<String, ParsedSql> parsedSqlCache = new LinkedHashMap<String, ParsedSql>(
+	@SuppressWarnings("serial") private final Map<String, ParsedSql> parsedSqlCache = new LinkedHashMap<>(
 			DEFAULT_CACHE_LIMIT, 0.75f, true) {
 		@Override
 		protected boolean removeEldestEntry(Map.Entry<String, ParsedSql> eldest) {

spring-data-r2dbc/src/main/java/org/springframework/data/r2dbc/core/NamedParameterUtils.java

@@ -384,11 +384,11 @@ int getEndIndex() {
 		public boolean equals(@Nullable Object o) {
 			if (this == o)
 				return true;
-			if (!(o instanceof ParameterHolder))
-				return false;
-			ParameterHolder that = (ParameterHolder) o;
-			return this.startIndex == that.startIndex && this.endIndex == that.endIndex
+			if (o instanceof ParameterHolder that) {
+				return this.startIndex == that.startIndex && this.endIndex == that.endIndex
 					&& Objects.equals(this.parameterName, that.parameterName);
+			}
+			return false;
 		}
 
 		@Override

spring-data-relational/src/main/java/org/springframework/data/relational/core/conversion/DbAction.java

@@ -209,7 +209,7 @@ public String toString() {
 	 * Note that deletes for contained entities that reference the root are to be represented by separate
 	 * {@link DbAction}s.
 	 * </p>
-	 * 
+	 *
 	 * @param <T> type of the entity for which this represents a database interaction.
 	 */
 	final class DeleteRoot<T> implements DbAction<T> {
@@ -274,7 +274,7 @@ public String toString() {
 	 * Note that deletes for contained entities that reference the root are to be represented by separate
 	 * {@link DbAction}s.
 	 * </p>
-	 * 
+	 *
 	 * @param <T> type of the entity for which this represents a database interaction.
 	 */
 	final class DeleteAllRoot<T> implements DbAction<T> {
@@ -467,7 +467,7 @@ interface WithDependingOn<T> extends WithPropertyPath<T>, WithEntity<T> {
 		 * <p>
 		 * Values come from parent entities but one might also add values manually.
 		 * </p>
-		 * 
+		 *
 		 * @return guaranteed to be not {@code null}.
 		 */
 		Map<PersistentPropertyPath<RelationalPersistentProperty>, Object> getQualifiers();
@@ -479,7 +479,7 @@ interface WithDependingOn<T> extends WithPropertyPath<T>, WithEntity<T> {
 		default Pair<PersistentPropertyPath<RelationalPersistentProperty>, Object> getQualifier() {
 
 			Map<PersistentPropertyPath<RelationalPersistentProperty>, Object> qualifiers = getQualifiers();
-			if (qualifiers.size() == 0)
+			if (qualifiers.isEmpty())
 				return null;
 
 			if (qualifiers.size() > 1) {

spring-data-relational/src/main/java/org/springframework/data/relational/core/dialect/MariaDbDialect.java

@@ -17,7 +17,6 @@
 
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Collections;
 
 import org.springframework.data.relational.core.sql.IdentifierProcessing;