Consistently declare Object::equals argument as @nullable

Author: sbrannen

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

@@ -117,7 +117,7 @@ private String replaceBooleanOperators(String pcExpr) {
 	}
 
 	@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 @@
 import java.io.Serializable;
 
 import org.springframework.aop.ClassFilter;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -45,7 +46,7 @@ public boolean matches(Class<?> candidate) {
 	}
 
 	@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 boolean matches(Class<?> clazz) {
 		}
 
 		@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.util.HashMap;
 import java.util.Map;
 
+import org.springframework.lang.Nullable;
+
 /**
  * Abstract superclass for counting advices etc.
  *
@@ -59,7 +61,7 @@ public int getCalls() {
 	 * @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 @@
 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 int getCount() {
 
 
 	@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

spring-aspects/src/test/java/org/springframework/cache/config/TestEntity.java

@@ -16,6 +16,7 @@
 
 package org.springframework.cache.config;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.ObjectUtils;
 
 /**
@@ -45,16 +46,11 @@ public int hashCode() {
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		if (obj == this) {
 			return true;
 		}
-		if (obj == null) {
-			return false;
-		}
-		if (obj instanceof TestEntity) {
-			return ObjectUtils.nullSafeEquals(this.id, ((TestEntity) obj).id);
-		}
-		return false;
+		return (obj instanceof TestEntity that && ObjectUtils.nullSafeEquals(this.id, that.id));
 	}
+
 }

spring-beans/src/test/java/org/springframework/beans/factory/DefaultListableBeanFactoryTests.java

@@ -2821,7 +2821,7 @@ public void setBeanName(String name) {
 		}
 
 		@Override
-		public boolean equals(Object o) {
+		public boolean equals(@Nullable Object o) {
 			if (this == o) {
 				return true;
 			}

spring-beans/src/test/java/org/springframework/beans/support/PagedListHolderTests.java

@@ -22,6 +22,7 @@
 import org.junit.jupiter.api.Test;
 
 import org.springframework.beans.testfixture.beans.TestBean;
+import org.springframework.lang.Nullable;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -194,7 +195,7 @@ public void setExtendedInfo(String extendedInfo) {
 		}
 
 		@Override
-		public boolean equals(Object o) {
+		public boolean equals(@Nullable Object o) {
 			if (this == o) {
 				return true;
 			}

spring-beans/src/testFixtures/java/org/springframework/beans/testfixture/beans/NestedTestBean.java

@@ -16,6 +16,8 @@
 
 package org.springframework.beans.testfixture.beans;
 
+import org.springframework.lang.Nullable;
+
 /**
  * Simple nested test bean used for testing bean factories, AOP framework etc.
  *
@@ -43,7 +45,7 @@ public String getCompany() {
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		if (!(obj instanceof NestedTestBean ntb)) {
 			return false;
 		}

spring-beans/src/testFixtures/java/org/springframework/beans/testfixture/beans/Pet.java

@@ -16,6 +16,8 @@
 
 package org.springframework.beans.testfixture.beans;
 
+import org.springframework.lang.Nullable;
+
 /**
  * @author Rob Harrop
  * @since 2.0
@@ -38,7 +40,7 @@ public String toString() {
 	}
 
 	@Override
-	public boolean equals(Object o) {
+	public boolean equals(@Nullable Object o) {
 		if (this == o) {
 			return true;
 		}