Why are arrays covariant but generics are invariant?

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From Effective Java by Joshua Bloch,

  1. Arrays differ from generic type in two important ways. First arrays are covariant. Generics are invariant.

  2. Covariant simply means if X is subtype of Y then X[] will also be sub type of Y[]. Arrays are covariant As string is subtype of Object So

    String[] is subtype of Object[]

    Invariant simply means irrespective of X being subtype of Y or not ,

     List<X> will not be subType of List<Y>.

My question is why the decision to make arrays covariant in Java? There are other SO posts such as Why are Arrays invariant, but Lists covariant?, but they seem to be focussed on Scala and I am not able to follow.

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