There are somewhat more involved formal treatments like Welterweight Java [1], which adds some more features, but of course, nowhere near the full set of Java features.
Some of the citations in that paper are also interesting.
I don't think there is a core calculus that specifically incorporates generics as in Java, but I could be wrong. In any case, much of Java's generics flow from theories of parametric polymorphism [2], specifically I believe bounded parametric polymorphism [3].
[1] https://www.researchgate.net/publication/220877645_Welterwei...
[2] https://www.cs.cmu.edu/~fp/courses/15814-f18/lectures/11-pol...