Check if an object is instance of List of given class name

I think you can do it in two steps: First, you check it's a List.

if (o instanceof List)

Then, you check that one (each?) member of the list has the given type.

for (Object obj : (List) o) {
    if (obj instanceof cls) {
        doSomething();
    }
}

It's because of Type Erasure. The statement

if (o instanceof List<cls>) {
  doSomething();
}

will be executed at runtime, when the generic type of the list will be erased. Therefore, there's no point of checking for instanceof generic-type.

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