Add Nullable annotation to parameter of overridden equals method.

Closes #1374
Original pull request #1375

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

@@ -382,7 +382,7 @@ abstract class NamedParameterUtils {
 		}
 
 		@Override
-		public boolean equals(Object o) {
+		public boolean equals(@Nullable Object o) {
 			if (this == o)
 				return true;
 			if (!(o instanceof ParameterHolder))

spring-data-r2dbc/src/main/java/org/springframework/data/r2dbc/mapping/OutboundRow.java

@@ -24,6 +24,7 @@ import java.util.Set;
 import java.util.function.BiConsumer;
 
 import org.springframework.data.relational.core.sql.SqlIdentifier;
+import org.springframework.lang.Nullable;
 import org.springframework.r2dbc.core.Parameter;
 import org.springframework.util.Assert;
 
@@ -195,7 +196,7 @@ public class OutboundRow implements Map<SqlIdentifier, Parameter>, Cloneable {
 	}
 
 	@Override
-	public boolean equals(final Object o) {
+	public boolean equals(@Nullable final Object o) {
 
 		if (this == o) {
 			return true;

spring-data-r2dbc/src/test/java/org/springframework/data/r2dbc/repository/AbstractR2dbcRepositoryWithMixedCaseNamesIntegrationTests.java

@@ -142,7 +142,7 @@ public abstract class AbstractR2dbcRepositoryWithMixedCaseNamesIntegrationTests
 		}
 
 		@Override
-		public boolean equals(Object o) {
+		public boolean equals(@Nullable Object o) {
 			if (this == o)
 				return true;
 			if (o == null || getClass() != o.getClass())