DelegatingAuthenticationEntryPoint.Builder is final

Make it final and a private constructor

Issue gh-17915

web/src/main/java/org/springframework/security/web/authentication/DelegatingAuthenticationEntryPoint.java

@@ -167,7 +167,7 @@ public class DelegatingAuthenticationEntryPoint implements AuthenticationEntryPo
 	 * @author Rob Winch
 	 * @since 7.0
 	 */
-	public static class Builder {
+	public static final class Builder {
 
 		private @Nullable AuthenticationEntryPoint defaultEntryPoint;
 
@@ -223,6 +223,9 @@ public class DelegatingAuthenticationEntryPoint implements AuthenticationEntryPo
 			return new DelegatingAuthenticationEntryPoint(defaultEntryPoint, this.entryPoints);
 		}
 
+		private Builder() {
+		}
+
 	}
 
 }