The Security Manager and APIs related to it have been deprecated and will be removed in a future release. To ensure that developers and users are aware that the Security Manager is deprecated for removal, the Java runtime issues a warning at startup if the Security Manager is enabled on the command line via `java -Djava.security.manager`. The Java runtime also issues a warning at run time if the Security Manager is enabled dynamically via the `System::setSecurityManager` API. These warnings cannot be disabled.

See [JEP 411](https://openjdk.java.net/jeps/411) for more information and a list of APIs that have been deprecated for removal.