Annotate Object#equals parameter with @Nullable

Closes gh-23093

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

@@ -720,7 +720,7 @@ public abstract class AbstractAspectJAdvice implements Advice, AspectJPrecedence
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}

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

@@ -519,7 +519,7 @@ public class AspectJExpressionPointcut extends AbstractExpressionPointcut
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

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

@@ -93,7 +93,7 @@ public class AspectJPointcutAdvisor implements PointcutAdvisor, Ordered {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-aop/src/main/java/org/springframework/aop/framework/AdvisedSupport.java

@@ -592,7 +592,7 @@ public class AdvisedSupport extends ProxyConfig implements Advised {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			return (this == other || (other instanceof MethodCacheKey &&
 					this.method == ((MethodCacheKey) other).method));
 		}

spring-aop/src/main/java/org/springframework/aop/framework/CglibAopProxy.java

@@ -349,7 +349,7 @@ class CglibAopProxy implements AopProxy, Serializable {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof CglibAopProxy &&
 				AopProxyUtils.equalsInProxy(this.advised, ((CglibAopProxy) other).advised)));
 	}
@@ -703,7 +703,7 @@ class CglibAopProxy implements AopProxy, Serializable {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			return (this == other ||
 					(other instanceof DynamicAdvisedInterceptor &&
 							this.advised.equals(((DynamicAdvisedInterceptor) other).advised)));
@@ -899,7 +899,7 @@ class CglibAopProxy implements AopProxy, Serializable {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}

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

@@ -65,7 +65,7 @@ public abstract class AbstractPointcutAdvisor implements PointcutAdvisor, Ordere
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

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

@@ -20,6 +20,7 @@ import java.io.Serializable;
 import java.lang.reflect.Method;
 import java.util.Arrays;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ObjectUtils;
@@ -195,7 +196,7 @@ public abstract class AbstractRegexpMethodPointcut extends StaticMethodMatcherPo
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-aop/src/main/java/org/springframework/aop/support/ClassFilters.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;
 import org.springframework.util.ObjectUtils;
 
@@ -106,7 +107,7 @@ public abstract class ClassFilters {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			return (this == other || (other instanceof UnionClassFilter &&
 					ObjectUtils.nullSafeEquals(this.filters, ((UnionClassFilter) other).filters)));
 		}
@@ -141,7 +142,7 @@ public abstract class ClassFilters {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			return (this == other || (other instanceof IntersectionClassFilter &&
 					ObjectUtils.nullSafeEquals(this.filters, ((IntersectionClassFilter) other).filters)));
 		}

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

@@ -21,6 +21,7 @@ import java.io.Serializable;
 import org.springframework.aop.ClassFilter;
 import org.springframework.aop.MethodMatcher;
 import org.springframework.aop.Pointcut;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -180,7 +181,7 @@ public class ComposablePointcut implements Pointcut, Serializable {
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

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

@@ -123,7 +123,7 @@ public class ControlFlowPointcut implements Pointcut, ClassFilter, MethodMatcher
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

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

@@ -150,7 +150,7 @@ public class DefaultIntroductionAdvisor implements IntroductionAdvisor, ClassFil
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

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

@@ -22,6 +22,7 @@ import java.lang.reflect.Method;
 import org.springframework.aop.ClassFilter;
 import org.springframework.aop.IntroductionAwareMethodMatcher;
 import org.springframework.aop.MethodMatcher;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -140,7 +141,7 @@ public abstract class MethodMatchers {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}
@@ -207,7 +208,7 @@ public abstract class MethodMatchers {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}
@@ -296,7 +297,7 @@ public abstract class MethodMatchers {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}

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

@@ -22,6 +22,7 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.PatternMatchUtils;
 
 /**
@@ -98,7 +99,7 @@ public class NameMatchMethodPointcut extends StaticMethodMatcherPointcut impleme
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof NameMatchMethodPointcut &&
 				this.mappedNames.equals(((NameMatchMethodPointcut) other).mappedNames)));
 	}

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

@@ -20,6 +20,7 @@ import java.lang.annotation.Annotation;
 
 import org.springframework.aop.ClassFilter;
 import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -67,7 +68,7 @@ public class AnnotationClassFilter implements ClassFilter {
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

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

@@ -120,7 +120,7 @@ public class AnnotationMatchingPointcut implements Pointcut {
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

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

@@ -23,6 +23,7 @@ import java.lang.reflect.Proxy;
 import org.springframework.aop.support.AopUtils;
 import org.springframework.aop.support.StaticMethodMatcher;
 import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -86,7 +87,7 @@ public class AnnotationMethodMatcher extends StaticMethodMatcher {
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/BeanMetadataAttribute.java

@@ -81,7 +81,7 @@ public class BeanMetadataAttribute implements BeanMetadataElement {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/ExtendedBeanInfo.java

@@ -339,7 +339,7 @@ class ExtendedBeanInfo implements BeanInfo {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			return (this == other || (other instanceof PropertyDescriptor &&
 					PropertyDescriptorUtils.equals(this, (PropertyDescriptor) other)));
 		}
@@ -491,7 +491,7 @@ class ExtendedBeanInfo implements BeanInfo {
 		 * See java.beans.IndexedPropertyDescriptor#equals(java.lang.Object)
 		 */
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}

spring-beans/src/main/java/org/springframework/beans/GenericTypeAwarePropertyDescriptor.java

@@ -163,7 +163,7 @@ final class GenericTypeAwarePropertyDescriptor extends PropertyDescriptor {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/MutablePropertyValues.java

@@ -367,7 +367,7 @@ public class MutablePropertyValues implements PropertyValues, Serializable {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof MutablePropertyValues &&
 				this.propertyValueList.equals(((MutablePropertyValues) other).propertyValueList)));
 	}

spring-beans/src/main/java/org/springframework/beans/PropertyValue.java

@@ -188,7 +188,7 @@ public class PropertyValue extends BeanMetadataAttributeAccessor implements Seri
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/InjectionPoint.java

@@ -176,7 +176,7 @@ public class InjectionPoint {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/annotation/InitDestroyAnnotationBeanPostProcessor.java

@@ -390,7 +390,7 @@ public class InitDestroyAnnotationBeanPostProcessor
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}

spring-beans/src/main/java/org/springframework/beans/factory/annotation/InjectionMetadata.java

@@ -296,7 +296,7 @@ public class InjectionMetadata {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}

spring-beans/src/main/java/org/springframework/beans/factory/config/BeanDefinitionHolder.java

@@ -166,7 +166,7 @@ public class BeanDefinitionHolder implements BeanMetadataElement {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/config/BeanExpressionContext.java

@@ -69,7 +69,7 @@ public class BeanExpressionContext {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/config/ConstructorArgumentValues.java

@@ -384,7 +384,7 @@ public class ConstructorArgumentValues {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/config/DependencyDescriptor.java

@@ -416,7 +416,7 @@ public class DependencyDescriptor extends InjectionPoint implements Serializable
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/config/RuntimeBeanNameReference.java

@@ -67,7 +67,7 @@ public class RuntimeBeanNameReference implements BeanReference {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/config/RuntimeBeanReference.java

@@ -92,7 +92,7 @@ public class RuntimeBeanReference implements BeanReference {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/config/TypedStringValue.java

@@ -215,7 +215,7 @@ public class TypedStringValue implements BeanMetadataElement {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/parsing/BeanComponentDefinition.java

@@ -128,7 +128,7 @@ public class BeanComponentDefinition extends BeanDefinitionHolder implements Com
 	 * as well, in addition to the superclass's equality requirements.
 	 */
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof BeanComponentDefinition && super.equals(other)));
 	}
 

spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractBeanDefinition.java

@@ -1152,7 +1152,7 @@ public abstract class AbstractBeanDefinition extends BeanMetadataAttributeAccess
 	public abstract AbstractBeanDefinition cloneBeanDefinition();
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/support/BeanDefinitionResource.java

@@ -22,6 +22,7 @@ import java.io.InputStream;
 
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.core.io.AbstractResource;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -80,7 +81,7 @@ class BeanDefinitionResource extends AbstractResource {
 	 * This implementation compares the underlying BeanDefinition.
 	 */
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof BeanDefinitionResource &&
 				((BeanDefinitionResource) other).beanDefinition.equals(this.beanDefinition)));
 	}

spring-beans/src/main/java/org/springframework/beans/factory/support/CglibSubclassingInstantiationStrategy.java

@@ -175,7 +175,7 @@ public class CglibSubclassingInstantiationStrategy extends SimpleInstantiationSt
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			return (getClass() == other.getClass() &&
 					this.beanDefinition.equals(((CglibIdentitySupport) other).beanDefinition));
 		}

spring-beans/src/main/java/org/springframework/beans/factory/support/ChildBeanDefinition.java

@@ -156,7 +156,7 @@ public class ChildBeanDefinition extends AbstractBeanDefinition {
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/support/GenericBeanDefinition.java

@@ -83,7 +83,7 @@ public class GenericBeanDefinition extends AbstractBeanDefinition {
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof GenericBeanDefinition && super.equals(other)));
 	}
 

spring-beans/src/main/java/org/springframework/beans/factory/support/LookupOverride.java

@@ -93,7 +93,7 @@ public class LookupOverride extends MethodOverride {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (!(other instanceof LookupOverride) || !super.equals(other)) {
 			return false;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/support/MethodOverride.java

@@ -105,7 +105,7 @@ public abstract class MethodOverride implements BeanMetadataElement {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/support/MethodOverrides.java

@@ -114,7 +114,7 @@ public class MethodOverrides {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/support/ReplaceOverride.java

@@ -20,6 +20,7 @@ import java.lang.reflect.Method;
 import java.util.LinkedList;
 import java.util.List;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
 
@@ -94,7 +95,7 @@ public class ReplaceOverride extends MethodOverride {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (!(other instanceof ReplaceOverride) || !super.equals(other)) {
 			return false;
 		}

spring-beans/src/main/java/org/springframework/beans/factory/support/RootBeanDefinition.java

@@ -452,7 +452,7 @@ public class RootBeanDefinition extends AbstractBeanDefinition {
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof RootBeanDefinition && super.equals(other)));
 	}
 

spring-beans/src/main/java/org/springframework/beans/support/MutableSortDefinition.java

@@ -18,6 +18,7 @@ package org.springframework.beans.support;
 
 import java.io.Serializable;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 
 /**
@@ -154,7 +155,7 @@ public class MutableSortDefinition implements SortDefinition, Serializable {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-context-support/src/main/java/org/springframework/cache/jcache/interceptor/JCacheOperationSourcePointcut.java

@@ -48,7 +48,7 @@ public abstract class JCacheOperationSourcePointcut extends StaticMethodMatcherP
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-context-support/src/main/java/org/springframework/mail/SimpleMailMessage.java

@@ -222,7 +222,7 @@ public class SimpleMailMessage implements MailMessage, Serializable {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-context/src/main/java/org/springframework/cache/annotation/AnnotationCacheOperationSource.java

@@ -164,7 +164,7 @@ public class AnnotationCacheOperationSource extends AbstractFallbackCacheOperati
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-context/src/main/java/org/springframework/cache/annotation/SpringCacheAnnotationParser.java

@@ -222,7 +222,7 @@ public class SpringCacheAnnotationParser implements CacheAnnotationParser, Seria
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || other instanceof SpringCacheAnnotationParser);
 	}
 

spring-context/src/main/java/org/springframework/cache/interceptor/CacheAspectSupport.java

@@ -836,7 +836,7 @@ public abstract class CacheAspectSupport extends AbstractCacheInvoker
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}

spring-context/src/main/java/org/springframework/cache/interceptor/CacheOperation.java

@@ -20,6 +20,7 @@ import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.Set;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -100,7 +101,7 @@ public abstract class CacheOperation implements BasicOperation {
 	 * @see #toString()
 	 */
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (other instanceof CacheOperation && toString().equals(other.toString()));
 	}
 

spring-context/src/main/java/org/springframework/cache/interceptor/CacheOperationSourcePointcut.java

@@ -49,7 +49,7 @@ abstract class CacheOperationSourcePointcut extends StaticMethodMatcherPointcut
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-context/src/main/java/org/springframework/cache/interceptor/NameMatchCacheOperationSource.java

@@ -110,7 +110,7 @@ public class NameMatchCacheOperationSource implements CacheOperationSource, Seri
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-context/src/main/java/org/springframework/cache/interceptor/SimpleKey.java

@@ -19,6 +19,7 @@ package org.springframework.cache.interceptor;
 import java.io.Serializable;
 import java.util.Arrays;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
@@ -54,7 +55,7 @@ public class SimpleKey implements Serializable {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other ||
 				(other instanceof SimpleKey && Arrays.deepEquals(this.params, ((SimpleKey) other).params)));
 	}

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClass.java

@@ -223,7 +223,7 @@ final class ConfigurationClass {
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof ConfigurationClass &&
 				getMetadata().getClassName().equals(((ConfigurationClass) other).getMetadata().getClassName())));
 	}

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java

@@ -1077,7 +1077,7 @@ class ConfigurationClassParser {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			return (this == other || (other instanceof SourceClass &&
 					this.metadata.getClassName().equals(((SourceClass) other).metadata.getClassName())));
 		}

spring-context/src/main/java/org/springframework/context/annotation/DeferredImportSelector.java

@@ -100,7 +100,7 @@ public interface DeferredImportSelector extends ImportSelector {
 			}
 
 			@Override
-			public boolean equals(Object other) {
+			public boolean equals(@Nullable Object other) {
 				if (this == other) {
 					return true;
 				}

spring-context/src/main/java/org/springframework/context/event/AbstractApplicationEventMulticaster.java

@@ -322,10 +322,13 @@ public abstract class AbstractApplicationEventMulticaster
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}
+			if (!(other instanceof ListenerCacheKey)) {
+				return false;
+			}
 			ListenerCacheKey otherKey = (ListenerCacheKey) other;
 			return (this.eventType.equals(otherKey.eventType) &&
 					ObjectUtils.nullSafeEquals(this.sourceType, otherKey.sourceType));

spring-context/src/main/java/org/springframework/context/expression/AnnotatedElementKey.java

@@ -51,7 +51,7 @@ public final class AnnotatedElementKey implements Comparable<AnnotatedElementKey
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-context/src/main/java/org/springframework/context/expression/CachedExpressionEvaluator.java

@@ -22,6 +22,7 @@ import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.expression.Expression;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
 
@@ -113,7 +114,7 @@ public abstract class CachedExpressionEvaluator {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}

spring-context/src/main/java/org/springframework/context/support/ApplicationListenerDetector.java

@@ -27,6 +27,7 @@ import org.springframework.beans.factory.support.MergedBeanDefinitionPostProcess
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.event.ApplicationEventMulticaster;
+import org.springframework.lang.Nullable;
 import org.springframework.util.ObjectUtils;
 
 /**
@@ -110,7 +111,7 @@ class ApplicationListenerDetector implements DestructionAwareBeanPostProcessor,
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof ApplicationListenerDetector &&
 				this.applicationContext == ((ApplicationListenerDetector) other).applicationContext));
 	}

spring-context/src/main/java/org/springframework/context/support/DefaultMessageSourceResolvable.java

@@ -170,7 +170,7 @@ public class DefaultMessageSourceResolvable implements MessageSourceResolvable,
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-context/src/main/java/org/springframework/format/support/FormattingConversionService.java

@@ -349,10 +349,13 @@ public class FormattingConversionService extends GenericConversionService
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}
+			if (!(other instanceof AnnotationConverterKey)) {
+				return false;
+			}
 			AnnotationConverterKey otherKey = (AnnotationConverterKey) other;
 			return (this.fieldType == otherKey.fieldType && this.annotation.equals(otherKey.annotation));
 		}

spring-context/src/main/java/org/springframework/jmx/access/MBeanClientInterceptor.java

@@ -654,7 +654,7 @@ public class MBeanClientInterceptor
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}

spring-context/src/main/java/org/springframework/jmx/support/NotificationListenerHolder.java

@@ -156,7 +156,7 @@ public class NotificationListenerHolder {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-context/src/main/java/org/springframework/scheduling/support/CronSequenceGenerator.java

@@ -428,7 +428,7 @@ public class CronSequenceGenerator {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-context/src/main/java/org/springframework/scheduling/support/CronTrigger.java

@@ -19,6 +19,7 @@ package org.springframework.scheduling.support;
 import java.util.Date;
 import java.util.TimeZone;
 
+import org.springframework.lang.Nullable;
 import org.springframework.scheduling.Trigger;
 import org.springframework.scheduling.TriggerContext;
 
@@ -89,7 +90,7 @@ public class CronTrigger implements Trigger {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof CronTrigger &&
 				this.sequenceGenerator.equals(((CronTrigger) other).sequenceGenerator)));
 	}

spring-context/src/main/java/org/springframework/scheduling/support/PeriodicTrigger.java

@@ -144,7 +144,7 @@ public class PeriodicTrigger implements Trigger {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-context/src/main/java/org/springframework/validation/AbstractBindingResult.java

@@ -360,7 +360,7 @@ public abstract class AbstractBindingResult extends AbstractErrors implements Bi
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-context/src/main/java/org/springframework/validation/BindException.java

@@ -299,7 +299,7 @@ public class BindException extends Exception implements BindingResult {
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || this.bindingResult.equals(other));
 	}
 

spring-core/src/main/java/org/springframework/core/AttributeAccessorSupport.java

@@ -92,7 +92,7 @@ public abstract class AttributeAccessorSupport implements AttributeAccessor, Ser
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof AttributeAccessorSupport &&
 				this.attributes.equals(((AttributeAccessorSupport) other).attributes)));
 	}

spring-core/src/main/java/org/springframework/core/MethodClassKey.java

@@ -50,7 +50,7 @@ public final class MethodClassKey implements Comparable<MethodClassKey> {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-core/src/main/java/org/springframework/core/MethodParameter.java

@@ -654,7 +654,7 @@ public class MethodParameter {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-core/src/main/java/org/springframework/core/ParameterizedTypeReference.java

@@ -20,6 +20,7 @@ package org.springframework.core;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -66,7 +67,7 @@ public abstract class ParameterizedTypeReference<T> {
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof ParameterizedTypeReference &&
 				this.type.equals(((ParameterizedTypeReference<?>) other).type)));
 	}

spring-core/src/main/java/org/springframework/core/ResolvableType.java

@@ -880,7 +880,7 @@ public class ResolvableType implements Serializable {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}
@@ -1549,7 +1549,7 @@ public class ResolvableType implements Serializable {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}

spring-core/src/main/java/org/springframework/core/convert/Property.java

@@ -263,7 +263,7 @@ public final class Property {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-core/src/main/java/org/springframework/core/convert/TypeDescriptor.java

@@ -452,7 +452,7 @@ public class TypeDescriptor implements Serializable {
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}
@@ -778,7 +778,7 @@ public class TypeDescriptor implements Serializable {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			return (this == other || (other instanceof AnnotatedElementAdapter &&
 					Arrays.equals(this.annotations, ((AnnotatedElementAdapter) other).annotations)));
 		}

spring-core/src/main/java/org/springframework/core/convert/support/GenericConversionService.java

@@ -458,7 +458,7 @@ public class GenericConversionService implements ConfigurableConversionService {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}

spring-core/src/main/java/org/springframework/core/env/PropertySource.java

@@ -132,7 +132,7 @@ public abstract class PropertySource<T> {
 	 * <p>No properties other than {@code name} are evaluated.
 	 */
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof PropertySource &&
 				ObjectUtils.nullSafeEquals(this.name, ((PropertySource<?>) other).name)));
 	}

spring-core/src/main/java/org/springframework/core/io/AbstractResource.java

@@ -215,7 +215,7 @@ public abstract class AbstractResource implements Resource {
 	 * @see #getDescription()
 	 */
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof Resource &&
 				((Resource) other).getDescription().equals(getDescription())));
 	}

spring-core/src/main/java/org/springframework/core/io/ByteArrayResource.java

@@ -115,7 +115,7 @@ public class ByteArrayResource extends AbstractResource {
 	 * @see java.util.Arrays#equals(byte[], byte[])
 	 */
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof ByteArrayResource &&
 				Arrays.equals(((ByteArrayResource) other).byteArray, this.byteArray)));
 	}

spring-core/src/main/java/org/springframework/core/io/ClassPathResource.java

@@ -244,7 +244,7 @@ public class ClassPathResource extends AbstractFileResolvingResource {
 	 * This implementation compares the underlying class path locations.
 	 */
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-core/src/main/java/org/springframework/core/io/DescriptiveResource.java

@@ -72,7 +72,7 @@ public class DescriptiveResource extends AbstractResource {
 	 * This implementation compares the underlying description String.
 	 */
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof DescriptiveResource &&
 				((DescriptiveResource) other).description.equals(this.description)));
 	}

spring-core/src/main/java/org/springframework/core/io/FileSystemResource.java

@@ -335,7 +335,7 @@ public class FileSystemResource extends AbstractResource implements WritableReso
 	 * This implementation compares the underlying File references.
 	 */
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof FileSystemResource &&
 				this.path.equals(((FileSystemResource) other).path)));
 	}

spring-core/src/main/java/org/springframework/core/io/InputStreamResource.java

@@ -115,7 +115,7 @@ public class InputStreamResource extends AbstractResource {
 	 * This implementation compares the underlying InputStream.
 	 */
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof InputStreamResource &&
 				((InputStreamResource) other).inputStream.equals(this.inputStream)));
 	}

spring-core/src/main/java/org/springframework/core/io/PathResource.java

@@ -32,6 +32,7 @@ import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.nio.file.StandardOpenOption;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -275,7 +276,7 @@ public class PathResource extends AbstractResource implements WritableResource {
 	 * This implementation compares the underlying Path references.
 	 */
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof PathResource &&
 				this.path.equals(((PathResource) other).path)));
 	}

spring-core/src/main/java/org/springframework/core/io/UrlResource.java

@@ -263,7 +263,7 @@ public class UrlResource extends AbstractFileResolvingResource {
 	 * This implementation compares the underlying URL references.
 	 */
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof UrlResource &&
 				this.cleanedUrl.equals(((UrlResource) other).cleanedUrl)));
 	}

spring-core/src/main/java/org/springframework/core/io/VfsResource.java

@@ -23,6 +23,7 @@ import java.net.URI;
 import java.net.URL;
 
 import org.springframework.core.NestedIOException;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -130,7 +131,7 @@ public class VfsResource extends AbstractResource {
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof VfsResource &&
 				this.resource.equals(((VfsResource) other).resource)));
 	}

spring-core/src/main/java/org/springframework/core/io/buffer/DefaultDataBuffer.java

@@ -24,6 +24,7 @@ import java.nio.ByteBuffer;
 import java.util.Arrays;
 import java.util.function.IntPredicate;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
 
@@ -411,7 +412,7 @@ public class DefaultDataBuffer implements DataBuffer {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-core/src/main/java/org/springframework/core/io/buffer/NettyDataBuffer.java

@@ -28,6 +28,7 @@ import io.netty.buffer.ByteBufInputStream;
 import io.netty.buffer.ByteBufOutputStream;
 import io.netty.buffer.ByteBufUtil;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
 
@@ -309,7 +310,7 @@ public class NettyDataBuffer implements PooledDataBuffer {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof NettyDataBuffer &&
 				this.byteBuf.equals(((NettyDataBuffer) other).byteBuf)));
 	}

spring-core/src/main/java/org/springframework/core/io/support/EncodedResource.java

@@ -161,7 +161,7 @@ public class EncodedResource implements InputStreamSource {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-core/src/main/java/org/springframework/core/type/classreading/SimpleAnnotationMetadataReadingVisitor.java

@@ -189,7 +189,7 @@ final class SimpleAnnotationMetadataReadingVisitor extends ClassVisitor {
 		}
 
 		@Override
-		public boolean equals(Object obj) {
+		public boolean equals(@Nullable Object obj) {
 			if (this == obj) {
 				return true;
 			}

spring-core/src/main/java/org/springframework/core/type/classreading/SimpleMethodMetadataReadingVisitor.java

@@ -127,7 +127,7 @@ final class SimpleMethodMetadataReadingVisitor extends MethodVisitor {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}

spring-core/src/main/java/org/springframework/util/AutoPopulatingList.java

@@ -25,6 +25,8 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.ListIterator;
 
+import org.springframework.lang.Nullable;
+
 /**
  * Simple {@link List} wrapper class that allows for elements to be
  * automatically populated as they are requested. This is particularly
@@ -231,7 +233,7 @@ public class AutoPopulatingList<E> implements List<E>, Serializable {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return this.backingList.equals(other);
 	}
 

spring-core/src/main/java/org/springframework/util/CollectionUtils.java

@@ -553,7 +553,7 @@ public abstract class CollectionUtils {
 		}
 
 		@Override
-		public boolean equals(Object other) {
+		public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}

spring-core/src/main/java/org/springframework/util/ConcurrentReferenceHashMap.java

@@ -758,7 +758,7 @@ public class ConcurrentReferenceHashMap<K, V> extends AbstractMap<K, V> implemen
 
 		@Override
 		@SuppressWarnings("rawtypes")
-		public final boolean equals(Object other) {
+		public final boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}

spring-core/src/main/java/org/springframework/util/LinkedCaseInsensitiveMap.java

@@ -273,7 +273,7 @@ public class LinkedCaseInsensitiveMap<V> implements Map<String, V>, Serializable
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		return this.targetMap.equals(obj);
 	}
 

spring-core/src/main/java/org/springframework/util/LinkedMultiValueMap.java

@@ -225,7 +225,7 @@ public class LinkedMultiValueMap<K, V> implements MultiValueMap<K, V>, Serializa
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		return this.targetMap.equals(obj);
 	}
 

spring-core/src/main/java/org/springframework/util/MimeType.java

@@ -420,7 +420,7 @@ public class MimeType implements Comparable<MimeType>, Serializable {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}

spring-core/src/main/java/org/springframework/util/comparator/BooleanComparator.java

@@ -19,6 +19,8 @@ package org.springframework.util.comparator;
 import java.io.Serializable;
 import java.util.Comparator;
 
+import org.springframework.lang.Nullable;
+
 /**
  * A {@link Comparator} for {@link Boolean} objects that can sort either
  * {@code true} or {@code false} first.
@@ -67,7 +69,7 @@ public class BooleanComparator implements Comparator<Boolean>, Serializable {
 
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof BooleanComparator &&
 				this.trueLow == ((BooleanComparator) other).trueLow));
 	}

spring-core/src/main/java/org/springframework/util/comparator/CompoundComparator.java

@@ -21,6 +21,7 @@ import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -187,7 +188,7 @@ public class CompoundComparator<T> implements Comparator<T>, Serializable {
 
 	@Override
 	@SuppressWarnings("unchecked")
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		return (this == other || (other instanceof CompoundComparator &&
 				this.comparators.equals(((CompoundComparator<T>) other).comparators)));
 	}

spring-core/src/main/java/org/springframework/util/comparator/InvertibleComparator.java

@@ -19,6 +19,7 @@ package org.springframework.util.comparator;
 import java.io.Serializable;
 import java.util.Comparator;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -108,7 +109,7 @@ public class InvertibleComparator<T> implements Comparator<T>, Serializable {
 
 	@Override
 	@SuppressWarnings("unchecked")
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}