Consistently declare Object::equals argument as @Nullable

spring-aop/src/main/java/org/springframework/aop/aspectj/TypePatternClassFilter.java

@@ -117,7 +117,7 @@ public class TypePatternClassFilter implements ClassFilter {
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		return (this == obj || (obj instanceof TypePatternClassFilter that &&
 				ObjectUtils.nullSafeEquals(this.typePattern, that.typePattern)));
 	}

spring-aop/src/main/java/org/springframework/aop/support/RootClassFilter.java

@@ -19,6 +19,7 @@ package org.springframework.aop.support;
 import java.io.Serializable;
 
 import org.springframework.aop.ClassFilter;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -45,7 +46,7 @@ public class RootClassFilter implements ClassFilter, Serializable {
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		return (this == obj || (obj instanceof RootClassFilter that &&
 				this.clazz.equals(that.clazz)));
 	}

spring-aop/src/main/java/org/springframework/aop/support/annotation/AnnotationMatchingPointcut.java

@@ -183,7 +183,7 @@ public class AnnotationMatchingPointcut implements Pointcut {
 		}
 
 		@Override
-		public boolean equals(Object obj) {
+		public boolean equals(@Nullable Object obj) {
 			if (this == obj) {
 				return true;
 			}

spring-aop/src/testFixtures/java/org/springframework/aop/testfixture/advice/MethodCounter.java

@@ -21,6 +21,8 @@ import java.lang.reflect.Method;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.springframework.lang.Nullable;
+
 /**
  * Abstract superclass for counting advices etc.
  *
@@ -59,7 +61,7 @@ public class MethodCounter implements Serializable {
 	 * @see java.lang.Object#equals(java.lang.Object)
 	 */
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (other != null && other.getClass() == this.getClass());
 	}
 

spring-aop/src/testFixtures/java/org/springframework/aop/testfixture/interceptor/NopInterceptor.java

@@ -19,6 +19,8 @@ package org.springframework.aop.testfixture.interceptor;
 import org.aopalliance.intercept.MethodInterceptor;
 import org.aopalliance.intercept.MethodInvocation;
 
+import org.springframework.lang.Nullable;
+
 /**
  * Trivial interceptor that can be introduced in a chain to display it.
  *
@@ -45,14 +47,14 @@ public class NopInterceptor implements MethodInterceptor {
 
 
 	@Override
-	public boolean equals(Object other) {
-		if (!(other instanceof NopInterceptor)) {
-			return false;
-		}
-		if (this == other) {
+	public boolean equals(@Nullable Object obj) {
+		if (this == obj) {
 			return true;
 		}
-		return this.count == ((NopInterceptor) other).count;
+		if (!(obj instanceof NopInterceptor that)) {
+			return false;
+		}
+		return this.count == that.count;
 	}
 
 	@Override