安全发布对象-发布与逸出

1.什么叫不安全发布，发布之后的对象会被其他对象不安全的改变值

@Slf4j
@NotThreadSafe
public class UnsafePublish {

  private String[] states = {"a", "b", "c"};

  public String[] getStates() {
    return states;
  }

  public static void main(String[] args) {
    UnsafePublish unsafePublish = new UnsafePublish();
    log.info("{}", Arrays.toString(unsafePublish.getStates()));
    unsafePublish.getStates()[0] = "d";
    log.info("{}", Arrays.toString(unsafePublish.getStates()));
  }
}

output

11:57:24.909 [main] INFO top.xiongmingcai.example.UnsafePublish - [a, b, c]
11:57:24.914 [main] INFO top.xiongmingcai.example.UnsafePublish - [d, b, c]

类初始化未结束，外部就可以使用他的this指针了。这里的逸代表的是逃逸的意思，提前逃出去了

@Slf4j
@NotRecommend
@NotThreadSafe
public class Escape {
  private int thisCanBeEscape = 0;

  public Escape() {
    new innerClass();
  }

  private class innerClass {
    public innerClass() {
    //在对象未构建之前不可以将其发布
      log.info("{}", Escape.this.thisCanBeEscape);
    }
  }

  public static void main(String[] args) {
    new Escape();
  }
}