许多JNI方法都通过返回值来指示调用成功与否。

Many JNI methods have a return value that indicates whether the call succeeded or not.

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函数调用成功时返回零，失败时返回非零的错误代码。

This call either returns zero on success or a non-zero error code on failure.

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如果调用成功，您应该看到带有这个意思的信息，如图9所示。

If the invocation is successful, you should see a message to that effect, as shown in Figure 9.

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I just doubled the indentation each time so you can see it. So each successive call, notice what's happening. The argument is getting reduced. And we're going another level in. When we get down to this point, we're calling it with just a string of length one.

因此每次成功调用注意它的过程,我们的命题不断简化，而且我们不断深入嵌套,当我们走到这一步的时候,我们就是在调用它处理，仅有一个元素的字符串了。

麻省理工公开课 - 计算机科学及编程导论课程节选