在 Java 中，对象何时变得不可访问? [英] In Java, when does an object become unreachable?

问题描述

在 Java 中，什么是不可访问对象?什么时候对象变得不可访问?在研究垃圾收集时，我无法理解这个概念.

In Java, what is an unreachable object? When does the object become unreachable? While studying garbage collection I was not able to understand this concept.

任何人都可以通过示例给出任何想法吗?

Can anyone give any ideas with examples?

推荐答案

当不再有任何引用变量引用它时，或者当它在孤岛中成为孤儿时.

When there are no longer any reference variables referring to it, OR when it is orphaned in an island.

岛是一个对象，它有一个指向它的引用变量，但是该对象没有指向它的引用变量.

An island being an object that has a reference variable pointing to it, however that object has no reference variables pointing to it.

class A { int i = 5; }
class B { A a = new A(); }
class C {
   B b;
   public static void main(String args[]) {
      C c = new C();
      c.b = new B();
      // instance of A, B, and C created
      c.b = null;
      // instance of B and A eligible to be garbage collected.
   }

只是想指出，即使 A 的实例有一个引用，它现在在一个岛上，因为 B 的实例没有对它的引用.A 实例符合垃圾回收条件.

Just want to point out that even though the instance of A has a reference, it is on an island now because the instance of B does not have a reference to it. The A instance is eligible for garbage collection.

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