SOOT class loading — what is a 'level'?

Question

From here :

The design of coffi requires that in order to bring some class C up to level N, you must first bring all classes that C references up to level N-1. In order to know which classes C references, you need to bring C up to level N-1.

What are these "levels"?

Answer 1

For performance reasons, Soot can load classes only to a certain level, eg only loading signatures but not bodies. Details can be seen in the class SootClass.