New "disallow" and "allow" token options have been added to the `java.security.manager` system property. In the JDK implementation, if the Java Virtual Machine starts with the system property `java.security.manager` set to "disallow", then the `System.setSecurityManager` method cannot be used to set a security manager and will throw an `UnsupportedOperationException`. The "disallow" option can improve run-time performance for applications that never set a security manager. For further details on the behavior of these options, see the class description of `java.lang.SecurityManager`.