Effective Java, CHAPTER 5 GENERICS, Item 25: Prefer lists to arrays:
Arrays differ from generic types in two important ways. First, arrays
are covariant. This scary-sounding word means simply that if Sub is a
subtype of Super, then the array type Sub[] is a subtype of Super[].
Generics, by contrast, are invariant: for any two distinct types Type1
and Type2, List<Type1> is neither a subtype nor a supertype of
List<Type2> ...
The second major difference between arrays and
generics is that arrays are reified [JLS, 4.7]. This means that arrays
know and enforce their element types at runtime. As noted above, if
you try to store a String into an array of Long, you’ll get an
ArrayStoreException. Generics, by contrast, are implemented by erasure
[JLS, 4.6]. This means that they enforce their type constraints only
at compile time and discard (or erase) their element type information
at runtime. Erasure is what allows generic types to interoperate
freely with legacy code that does not use generics (Item 23). Because
of these fundamental differences, arrays and generics do not mix well.
For example, it is illegal to create an array of a generic type, a
parameterized type, or a type parameter. None of these array creation
expressions are legal: new List[], new List[], new E[]. All
will result in generic array creation errors at compile time.
Long story short: Arrays and Generics have kind of "opposite" characteristics which makes it very difficult, if not impossible in some situations, to mix them, so better take Joshua Bloch's word on it and use Lists instead of arrays when generics are involves .
