finalize()是对JVM的一个提示，建议在未指定的时间执行代码。当您希望代码莫名其妙地无法运行时，这是很好的方法。

在终结器中做任何重要的事情(基本上除了日志)在三种情况下也很好:

您希望打赌其他已完成的对象仍然处于程序其余部分认为有效的状态。 您希望向所有具有终结器的类的所有方法添加大量检查代码，以确保它们在终结后行为正确。 您希望意外地复活已完成的对象，并花费大量时间试图弄清楚为什么它们不起作用，和/或为什么它们在最终释放时没有最终完成。

If you think you need finalize(), sometimes what you really want is a phantom reference (which in the example given could hold a hard reference to a connection used by its referand, and close it after the phantom reference has been queued). This also has the property that it may mysteriously never run, but at least it can't call methods on or resurrect finalized objects. So it's just right for situations where you don't absolutely need to close that connection cleanly, but you'd quite like to, and the clients of your class can't or won't call close themselves (which is actually fair enough - what's the point of having a garbage collector at all if you design interfaces that require a specific action be taken prior to collection? That just puts us back in the days of malloc/free.)

Other times you need the resource you think you're managing to be more robust. For example, why do you need to close that connection? It must ultimately be based on some kind of I/O provided by the system (socket, file, whatever), so why can't you rely on the system to close it for you when the lowest level of resource is gced? If the server at the other end absolutely requires you to close the connection cleanly rather than just dropping the socket, then what's going to happen when someone trips over the power cable of the machine your code is running on, or the intervening network goes out?

免责声明:我以前在JVM实现上工作过。我讨厌终结者。

Be careful about what you do in a finalize(). Especially if you are using it for things like calling close() to ensure that resources are cleaned up. We ran into several situations where we had JNI libraries linked in to the running java code, and in any circumstances where we used finalize() to invoke JNI methods, we would get very bad java heap corruption. The corruption was not caused by the underlying JNI code itself, all of the memory traces were fine in the native libraries. It was just the fact that we were calling JNI methods from the finalize() at all.

这是JDK 1.5，它仍然在广泛使用。

直到很久以后，我们才发现出了问题，但最终罪魁祸首始终是使用JNI调用的finalize()方法。

iirc——你可以使用finalize方法作为实现昂贵资源池机制的一种手段——这样它们就不会得到GC了。

资源(文件，套接字，流等)需要关闭一旦我们完成他们。它们通常有close()方法，我们通常在try-catch语句的finally部分调用该方法。有时finalize()也可以被少数开发人员使用，但在我看来，这不是一种合适的方式，因为不能保证finalize总是被调用。

在Java 7中，我们有try-with-resources语句，可以这样使用:

try (BufferedReader br = new BufferedReader(new FileReader(path))) {
  // Processing and other logic here.
} catch (Exception e) {
  // log exception
} finally {
  // Just in case we need to do some stuff here.
}

在上面的例子中，try-with-resource将通过调用close()方法自动关闭资源BufferedReader。如果我们愿意，我们也可以在自己的类中实现Closeable，并以类似的方式使用它。在我看来，这似乎更整洁，更容易理解。

finalize()是对JVM的一个提示，建议在未指定的时间执行代码。当您希望代码莫名其妙地无法运行时，这是很好的方法。

在终结器中做任何重要的事情(基本上除了日志)在三种情况下也很好:

您希望打赌其他已完成的对象仍然处于程序其余部分认为有效的状态。 您希望向所有具有终结器的类的所有方法添加大量检查代码，以确保它们在终结后行为正确。 您希望意外地复活已完成的对象，并花费大量时间试图弄清楚为什么它们不起作用，和/或为什么它们在最终释放时没有最终完成。

If you think you need finalize(), sometimes what you really want is a phantom reference (which in the example given could hold a hard reference to a connection used by its referand, and close it after the phantom reference has been queued). This also has the property that it may mysteriously never run, but at least it can't call methods on or resurrect finalized objects. So it's just right for situations where you don't absolutely need to close that connection cleanly, but you'd quite like to, and the clients of your class can't or won't call close themselves (which is actually fair enough - what's the point of having a garbage collector at all if you design interfaces that require a specific action be taken prior to collection? That just puts us back in the days of malloc/free.)

Other times you need the resource you think you're managing to be more robust. For example, why do you need to close that connection? It must ultimately be based on some kind of I/O provided by the system (socket, file, whatever), so why can't you rely on the system to close it for you when the lowest level of resource is gced? If the server at the other end absolutely requires you to close the connection cleanly rather than just dropping the socket, then what's going to happen when someone trips over the power cable of the machine your code is running on, or the intervening network goes out?

免责声明:我以前在JVM实现上工作过。我讨厌终结者。

当编写将被其他开发人员使用的代码时，需要调用某种“清理”方法来释放资源。有时那些其他开发人员忘记调用您的清理(或关闭，或销毁，或其他)方法。为了避免可能的资源泄漏，您可以检查finalize方法，以确保该方法被调用，如果没有调用，您可以自己调用它。

许多数据库驱动程序在它们的Statement和Connection实现中这样做，以提供一点安全性，防止开发人员忘记调用close。