Add Nullable annotation to parameter of overridden equals method.

Closes: #1325
Original pull request: #1326

Author: christophstrobl

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/config/KeyspaceActions.java

@@ -19,6 +19,7 @@
 import java.util.List;
 
 import org.springframework.data.cassandra.core.cql.keyspace.KeyspaceActionSpecification;
+import org.springframework.lang.Nullable;
 import org.springframework.util.ObjectUtils;
 
 /**
@@ -44,7 +45,7 @@ public List<KeyspaceActionSpecification> getActions() {
 	}
 
 	@Override
-	public boolean equals(Object o) {
+	public boolean equals(@Nullable Object o) {
 
 		if (this == o) {
 			return true;

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/core/DeleteOptions.java

@@ -105,7 +105,7 @@ public Filter getIfCondition() {
 	}
 
 	@Override
-	public boolean equals(Object o) {
+	public boolean equals(@Nullable Object o) {
 
 		if (this == o) {
 			return true;

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/core/InsertOptions.java

@@ -103,7 +103,7 @@ public boolean isInsertNulls() {
 	}
 
 	@Override
-	public boolean equals(Object o) {
+	public boolean equals(@Nullable Object o) {
 
 		if (this == o) {
 			return true;

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/core/UpdateOptions.java

@@ -107,7 +107,7 @@ public boolean isIfExists() {
 	}
 
 	@Override
-	public boolean equals(Object o) {
+	public boolean equals(@Nullable Object o) {
 
 		if (this == o) {
 			return true;

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/core/convert/SchemaFactory.java

@@ -32,6 +32,7 @@
 import org.springframework.data.convert.CustomConversions;
 import org.springframework.data.mapping.MappingException;
 import org.springframework.data.mapping.context.MappingContext;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 import com.datastax.oss.driver.api.core.CqlIdentifier;
@@ -402,7 +403,7 @@ public void attach(@edu.umd.cs.findbugs.annotations.NonNull AttachmentPoint atta
 		}
 
 		@Override
-		public boolean equals(Object o) {
+		public boolean equals(@Nullable Object o) {
 			if (this == o)
 				return true;
 			if (!(o instanceof com.datastax.oss.driver.api.core.type.UserDefinedType))

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/core/cql/CqlIdentifier.java

@@ -18,6 +18,7 @@
 import java.io.Serializable;
 import java.util.regex.Pattern;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -237,7 +238,7 @@ public int compareTo(CqlIdentifier identifier) {
 	 * @see java.lang.Object#equals(java.lang.Object)
 	 */
 	@Override
-	public boolean equals(Object o) {
+	public boolean equals(@Nullable Object o) {
 
 		if (this == o)
 			return true;

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/core/cql/KeyspaceIdentifier.java

@@ -17,6 +17,7 @@
 
 import java.util.regex.Pattern;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 import com.datastax.oss.driver.api.core.CqlIdentifier;
@@ -118,7 +119,7 @@ public int hashCode() {
 	 * equal to a {@link KeyspaceIdentifier}.
 	 */
 	@Override
-	public boolean equals(Object that) {
+	public boolean equals(@Nullable Object that) {
 		if (this == that) {
 			return true;
 		}

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/core/cql/QueryOptions.java

@@ -213,7 +213,7 @@ protected Boolean getTracing() {
 	}
 
 	@Override
-	public boolean equals(Object o) {
+	public boolean equals(@Nullable Object o) {
 
 		if (this == o) {
 			return true;

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/core/cql/WriteOptions.java

@@ -108,7 +108,7 @@ public Long getTimestamp() {
 	}
 
 	@Override
-	public boolean equals(Object o) {
+	public boolean equals(@Nullable Object o) {
 
 		if (this == o) {
 			return true;

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/core/cql/keyspace/CreateKeyspaceSpecification.java

@@ -152,7 +152,7 @@ public CreateKeyspaceSpecification with(String name, @Nullable Object value, boo
 	}
 
 	@Override
-	public boolean equals(Object o) {
+	public boolean equals(@Nullable Object o) {
 
 		if (this == o) {
 			return true;