31 lines
972 B
Java
31 lines
972 B
Java
// generics/CovariantArrays.java
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// (c)2016 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://mindviewinc.com/Books/OnJava/ for more book information.
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class Fruit {}
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class Apple extends Fruit {}
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class Jonathan extends Apple {}
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class Orange extends Fruit {}
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public class CovariantArrays {
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public static void main(String[] args) {
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Fruit[] fruit = new Apple[10];
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fruit[0] = new Apple(); // OK
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fruit[1] = new Jonathan(); // OK
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// Runtime type is Apple[], not Fruit[] or Orange[]:
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try {
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// Compiler allows you to add Fruit:
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fruit[0] = new Fruit(); // ArrayStoreException
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} catch(Exception e) { System.out.println(e); }
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try {
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// Compiler allows you to add Oranges:
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fruit[0] = new Orange(); // ArrayStoreException
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} catch(Exception e) { System.out.println(e); }
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}
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}
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/* Output:
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java.lang.ArrayStoreException: Fruit
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java.lang.ArrayStoreException: Orange
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*/
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