Frequently asked questions (FAQ)

Why do artifact scanners detect vulnerabilities in recipe artifacts/JARs?

In order to modernize and upgrade old or vulnerable code, some OpenRewrite recipe modules bundle copies of old libraries. Libraries bundled into recipe modules are never executed. That being said, these libraries are never executed.

OpenRewrite exercises the Java compiler internally to compile code patterns that exist in these old and/or vulnerable libraries. These patterns are then used to match old or vulnerable code for the sake of modernizing or repairing it.

Using a library in compilation in this way does not trigger class initialization in the way that reflection might, for example. In other words, code paths in libraries used in compilation are never executed.

As an example of this, consider the case of rewrite-spring. It has libraries bundled inside of the META-INF/rewrite/classpath directory. However, those JARs are not made into a Fat Jar or a shaded library in the traditional sense. It is not possible that by using rewrite-spring that one of those libraries gets called.