How to Find native methods from a java bytecode

[rupeshkoushik07]

In SootUp, what algorithm is used to walk the class hierarchy, and how does it detect that a given method is implemented natively?

[JonasKlauke]

Native methods have a native modifier. There is a isNative method to check if a given method is native.
If you want to find all native methods of your view you could do this:

List<JavaSootMethod> natives=view.getClasses()
  .flatMap(javaSootClass -> javaSootClass.getMethods().stream())
  .filter(JavaSootMethod::isNative)
  .toList();