Narcissus is a JNI native code library that provides a small subset of the Java reflection API, while bypassing all of Java’s access/visibility checks, security manager restrictions, and module strong encapsulation enforcement, by calling methods and accessing fields through the JNI API. This allows code that relies on reflective access to non-public classes, fields, and methods to keep working even now that strong encapsulation is being enforced in JDK 16+.

Narcissus works on JDK 7+, however it is most useful for suppressing reflective access warnings in JDK 9-15, and for circumventing strong encapsulation for JDK 16+, in order to keep legacy software running (for example, when legacy software depends upon setAccessible to access a needed private field of a class in some library).