Java 编程思想中关于泛型存在不理解的地方 - V2EX
stdying
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Java 编程思想中关于泛型存在不理解的地方

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  •   stdying May 30, 2018 2707 views
    This topic created in 2905 days ago, the information mentioned may be changed or developed.
    因为有了擦除,数组的运行时类型就只能是 Object[],如果我们立即将其转型为 T[],在编译期该数组的实际类型就会丢失,而编译器可能会错过某些潜在的错误检查。

    为何在编译器会丢失,
    使用 Object[] ,是不是就不会丢失,

    要理解这部分,还需要那部分知识。

    谢谢
    3 replies    2018-05-31 10:32:33 +08:00
    qwertty01
        1
    qwertty01  
       May 30, 2018
    书上已经说的很明白了,为了兼容旧代码,所以需要编译器丢失泛型相关的信息。具体在 15.7.2 迁移兼容性

    你如果使用 Object[],你就没有啥可以失去(擦除)的了。

    看《深入理解 Java 虚拟机》
    msg7086
        2
    msg7086  
       May 31, 2018
    用 Object,已经被擦没了,就没有什么好害怕的了。
    究其原因是以前 Java 没有泛型,所以后来的泛型实现为了兼容以前不支持泛型的环境,只能做成伪泛型。
    stdying
        3
    stdying  
    OP
       May 31, 2018
    @qwertty01 好的,谢谢
    @msg7086 好的,谢谢
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