数组与泛型的不同点

  1. 数组是协变的(covariant)，泛型是不可变的(invariant)
  2. 数组是具体化的(reified)
// Fails at runtime!
Object[] objectArray = new Long[1];
objectArray[0] = "I don't fit in"; // Throws ArrayStoreException

// Won't compile!
List<Object> ol = new ArrayList<Long>(); // Incompatible types
ol.add("I don't fit in");

创建泛型数组是非法的

new List<E>[] new List<String>[] new E[]