Java 9 Cleaner 正确用法

Question

阅读有关 Java 9 的文章 Cleaner类，我在同一页中找到了这个示例:

public class CleaningExample implements AutoCloseable {
    // A cleaner, preferably one shared within a library
    private static final Cleaner cleaner = <cleaner>;

    static class State implements Runnable {

        State(...) {
            // initialize State needed for cleaning action
        }

        public void run() {
            // cleanup action accessing State, executed at most once
        }
    }

    private final State;
    private final Cleaner.Cleanable cleanable

    public CleaningExample() {
        this.state = new State(...);
        this.cleanable = cleaner.register(this, state);
    }

    public void close() {
        cleanable.clean();
    }
}

在第二行有一条评论说:

A cleaner, preferably one shared within a library

为什么在一个库中共享一个 Cleaner(静态)更好？

有没有人有关于如何使用 Cleaner 而不是覆盖 finalize() 的好例子？

Answer 1

Why is it preferable to have one shared Cleaner (static) within a library?

清洁器有一个关联的线程。线程是有限的 native 资源。因此，我们的目标是通过不创建不必要的清洁器来限制创建的线程数量。

Does anybody have a good example about how to use Cleaner instead of overriding finalize()?

您发布了引用示例。如果这还不够，您需要提出更具体的问题。