Unchecked exceptions which are descendents of RuntimeException class are the ideal candidate exceptions handle non-recoverable errors such as resource non-availability or some null Pointers.

未检查异常作为运行时exception类是理想的异常侯选处理不可恢复性出错，如资源不可用或者空指针。

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You might wonder about the String class given the issue of out-of-order writes and a reference becoming non-null prior to the constructor executing. Consider the following code.

鉴于无序写入和引用在构造函数执行前变成非null的问题，您可能会考虑string类。

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