当无法分配变量时，可能已经分配了变量 [英] variable might already have been assigned when it cannot be assigned

问题描述

研究此代码：

public class TestFinalAndCatch {
    private final int i;

    TestFinalAndCatch(String[] args) {
        try {
            i = method1();
        } catch (IOException ex) {
            i = 0;  // error: variable i might already have been assigned
        }
    }

    static int method1() throws IOException {
        return 1;
    }
}

编译器说 java：变量我可能已被分配

但对我来说这看起来是不可能的情况。

But for me it is looks like impossible situation.

推荐答案

i 是最终的，因此只能分配一次。编译器可能不够聪明，无法实现如果抛出异常，则不会发生第一个赋值，如果不抛出异常，则不会发生第二个赋值。

i is final, so it can only be assigned once. The compiler is probably not smart enough to realize that if an exception is thrown, the first assignment won't take place, and if an exception isn't thrown, the second assignment won't take place.

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