finally块总是在Java中执行吗？ [英] Does a finally block always get executed in Java?

问题描述

考虑到这段代码，我可以完全确定 finally 块始终执行，无论是什么（ ）是？

Considering this code, can I be absolutely sure that the finally block always executes, no matter what something() is?

try {  
    something();  
    return success;  
}  
catch (Exception e) {   
    return failure;  
}  
finally {  
    System.out.println("i don't know if this will get printed out.");
}

推荐答案

是的， finally 将在执行try或catch代码块后调用。

Yes, finally will be called after the execution of the try or catch code blocks.

唯一的时间 finally 将不会被调用：

The only times finally won't be called are:

1. 如果你调用 System.exit（）;


2. 如果JVM首先崩溃;


3. 如果JVM达到无限循环（或其他一些不可中断的，非终止声明）在尝试或捕获块;


4. 如果操作系统强行终止JVM进程;例如UNIX上的kill -9。


5. 如果主机系统死机;例如电源故障，硬件错误，操作系统恐慌等等。


6. 如果最后一个块将由守护程序线程执行，并且所有其他非守护程序线程在最终被调用之前退出。

1. If you invoke System.exit();
2. If the JVM crashes first;
3. If the JVM reaches an infinite loop (or some other non-interruptable, non-terminating statement) in the try or catch block;
4. If the OS forcibly terminates the JVM process; e.g. "kill -9 " on UNIX.
5. If the host system dies; e.g. power failure, hardware error, OS panic, etcetera.
6. If finally block is going to be executed by daemon thread and all other non daemon threads exit before finally is called.

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