For those that enable the SecurityManager at runtime via tSecurityManager, they have to specify the 'allow' option as of JDK 18 (see JDK-8203316). Many applications and frameworks are designed to run on multiple JDKs. In JDK 12, two new token options for the system property, 'allow' and 'disallow', were introduced. Security-libs/curity ➜ Ignore Allow and Disallow Options for System Property