// arrays/ArrayOfGenerics.java

// (c)2017 MindView LLC: see Copyright.txt

// We make no guarantees that this code is fit for any purpose.

// Visit http://OnJava8.com for more book information.

import java.util.*;

public class ArrayOfGenerics {

@SuppressWarnings("unchecked")

public static void main(String[] args) {

List<String>[] ls;

List[] la = new List[10];

ls = (List<String>[])la; // Unchecked cast

ls[0] = new ArrayList<>();

//- ls[1] = new ArrayList<Integer>();

// error: incompatible types: ArrayList<Integer>

// cannot be converted to List<String>

// ls[1] = new ArrayList<Integer>();

// ^

// The problem: List<String> is a subtype of Object

Object[] objects = ls; // So assignment is OK

// Compiles and runs without complaint:

objects[1] = new ArrayList<>();

// However, if your needs are straightforward it is

// possible to create an array of generics, albeit

// with an "unchecked cast" warning:

List<BerylliumSphere>[] spheres =

(List<BerylliumSphere>[])new List[10];

Arrays.setAll(spheres, n -> new ArrayList<>());

}

}