diff --git a/oauth2/oauth2-core/src/main/java/org/springframework/security/oauth2/core/OAuth2AuthenticatedPrincipal.java b/oauth2/oauth2-core/src/main/java/org/springframework/security/oauth2/core/OAuth2AuthenticatedPrincipal.java
index f056aba43d..17be893e94 100644
--- a/oauth2/oauth2-core/src/main/java/org/springframework/security/oauth2/core/OAuth2AuthenticatedPrincipal.java
+++ b/oauth2/oauth2-core/src/main/java/org/springframework/security/oauth2/core/OAuth2AuthenticatedPrincipal.java
@@ -39,6 +39,7 @@ public interface OAuth2AuthenticatedPrincipal extends AuthenticatedPrincipal {
 	 * @return the attribute or {@code null} otherwise
 	 */
 	@Nullable
+	@SuppressWarnings("unchecked")
 	default <A> A getAttribute(String name) {
 		return (A) getAttributes().get(name);
 	}
diff --git a/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/authentication/JwtGrantedAuthoritiesConverter.java b/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/authentication/JwtGrantedAuthoritiesConverter.java
index 271e4c3c90..ab020a3fc8 100644
--- a/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/authentication/JwtGrantedAuthoritiesConverter.java
+++ b/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/authentication/JwtGrantedAuthoritiesConverter.java
@@ -118,9 +118,14 @@ public final class JwtGrantedAuthoritiesConverter implements Converter<Jwt, Coll
 			return Collections.emptyList();
 		}
 		if (authorities instanceof Collection) {
-			return (Collection<String>) authorities;
+			return castAuthoritiesToCollection(authorities);
 		}
 		return Collections.emptyList();
 	}
 
+	@SuppressWarnings("unchecked")
+	private Collection<String> castAuthoritiesToCollection(Object authorities) {
+		return (Collection<String>) authorities;
+	}
+
 }