diff --git a/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/OAuth2Authorization.java b/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/OAuth2Authorization.java
index 035c57a8fb..b65f5343ac 100644
--- a/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/OAuth2Authorization.java
+++ b/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/OAuth2Authorization.java
@@ -196,7 +196,7 @@ public Map<String, Object> getAttributes() {
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		if (this == obj) {
 			return true;
 		}
@@ -363,7 +363,7 @@ protected static Map<String, Object> defaultMetadata() {
 		}
 
 		@Override
-		public boolean equals(Object obj) {
+		public boolean equals(@Nullable Object obj) {
 			if (this == obj) {
 				return true;
 			}
diff --git a/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/OAuth2AuthorizationConsent.java b/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/OAuth2AuthorizationConsent.java
index 19151f7825..778de48e4f 100644
--- a/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/OAuth2AuthorizationConsent.java
+++ b/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/OAuth2AuthorizationConsent.java
@@ -24,6 +24,8 @@
 import java.util.Set;
 import java.util.function.Consumer;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.security.core.GrantedAuthority;
 import org.springframework.security.core.authority.SimpleGrantedAuthority;
 import org.springframework.security.oauth2.server.authorization.client.RegisteredClient;
@@ -107,7 +109,7 @@ public Set<String> getScopes() {
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		if (this == obj) {
 			return true;
 		}
diff --git a/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/OAuth2TokenType.java b/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/OAuth2TokenType.java
index b4413d8b4f..ebf47190e5 100644
--- a/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/OAuth2TokenType.java
+++ b/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/OAuth2TokenType.java
@@ -19,6 +19,8 @@
 import java.io.Serial;
 import java.io.Serializable;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.util.Assert;
 
 /**
@@ -64,7 +66,7 @@ public String getValue() {
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		if (this == obj) {
 			return true;
 		}
diff --git a/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2TokenExchangeActor.java b/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2TokenExchangeActor.java
index f4de6b65a0..3c5c4ac071 100644
--- a/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2TokenExchangeActor.java
+++ b/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2TokenExchangeActor.java
@@ -22,6 +22,8 @@
 import java.util.Map;
 import java.util.Objects;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.security.oauth2.core.ClaimAccessor;
 import org.springframework.security.oauth2.server.authorization.token.OAuth2TokenClaimNames;
 import org.springframework.util.Assert;
@@ -65,7 +67,7 @@ public String getSubject() {
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		if (!(obj instanceof OAuth2TokenExchangeActor other)) {
 			return false;
 		}
diff --git a/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/client/RegisteredClient.java b/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/client/RegisteredClient.java
index 5367cd1abb..8bcf645715 100644
--- a/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/client/RegisteredClient.java
+++ b/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/client/RegisteredClient.java
@@ -203,7 +203,7 @@ public TokenSettings getTokenSettings() {
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		if (this == obj) {
 			return true;
 		}
diff --git a/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/settings/AbstractSettings.java b/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/settings/AbstractSettings.java
index d26479abd3..70fa7ed8fe 100644
--- a/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/settings/AbstractSettings.java
+++ b/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/settings/AbstractSettings.java
@@ -67,7 +67,7 @@ public Map<String, Object> getSettings() {
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		if (this == obj) {
 			return true;
 		}
diff --git a/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/settings/OAuth2TokenFormat.java b/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/settings/OAuth2TokenFormat.java
index ae4a97be2c..ffba370f96 100644
--- a/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/settings/OAuth2TokenFormat.java
+++ b/oauth2/oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/settings/OAuth2TokenFormat.java
@@ -19,6 +19,8 @@
 import java.io.Serial;
 import java.io.Serializable;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.util.Assert;
 
 /**
@@ -65,7 +67,7 @@ public String getValue() {
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		if (this == obj) {
 			return true;
 		}
diff --git a/webauthn/src/main/java/org/springframework/security/web/webauthn/api/ImmutablePublicKeyCredentialUserEntity.java b/webauthn/src/main/java/org/springframework/security/web/webauthn/api/ImmutablePublicKeyCredentialUserEntity.java
index 39f62c1e46..27c60ad277 100644
--- a/webauthn/src/main/java/org/springframework/security/web/webauthn/api/ImmutablePublicKeyCredentialUserEntity.java
+++ b/webauthn/src/main/java/org/springframework/security/web/webauthn/api/ImmutablePublicKeyCredentialUserEntity.java
@@ -137,7 +137,7 @@ public static PublicKeyCredentialUserEntityBuilder builder() {
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		if (this == obj) {
 			return true;
 		}