A generics self-check tests invariant containers, wildcard bounds and the compiler's choice of a method overload.
Review the contracts
Review generic bounds, overload selection, cast boundaries before answering.
Choose and explain an answer
Track the static type and captured bound instead of substituting a value observed in one run. Determine what the compiler can permit for every legal caller.
Select an answer for every question, then check the result and read each explanation. Progress remains in this browser; this is a self-check, not a judged program submission or a credential.
Common Mistakes
A List of one numeric subtype is not a List of every numeric subtype. A cast does not validate each generic element.