创建本地和实例对象时出现java StackOverflowError [英] java StackOverflowError when local and instance objects creation

问题描述

您好，有人可以向我解释一下为什么此代码段给了我StackOverflowError 如果您能解释instanceObj初始化并调用ObjectTest构造函数和java.lang.Object构造函数时发生的情况，我将不胜感激.在我看来，ObjectTest构造函数会不断循环.但是我不知道确切的原因吗​​?所以有什么建议...

Hi can anybody please explain me why is this code snippet giving me StackOverflowError I really appreciate if you can explain what is happening when instanceObj initializing and calling ObjectTest constructor and java.lang.Object constructor. It seems to me ObjectTest constructor loop over and over.But I don't know exact reason? So any suggestion...

public class ObjectTest {

  public ObjectTest() {

   }


  ObjectTest instanceObj = new ObjectTest();


  public static void main(String[] args) {

     ObjectTest localObj = new ObjectTest();
   }
}

推荐答案

让我们看看将执行什么:

Let's see what will be executed :

1. main()创建ObjectTest
的新实例
2. ObjectTest类具有一个字段instanceObj，该字段将包含一个ObjectTest
3. instanceObj用新的ObjectTest
初始化
4. 转到第2步

1. main() create a new instance of ObjectTest
2. the ObjectTest class has a field instanceObj which will contain an ObjectTest
3. the instanceObj in initialized with a new ObjectTest
4. go to step 2

---

我认为您想要更多类似这样的东西:

---

I think you wanted something more like this :

public class ObjectTest {
    private static ObjectTest instanceObj;

    private ObjectTest() {
    }

    public static ObjectTest getInstance() {
        if (instanceObj != null) {
            instanceObj = new ObjectTest();
        }
        return instanceObj;
    }

    public static void main(String[] args) {

        ObjectTest localObj = ObjectTest.getInstance();
    }
}

或者这个:

public class ObjectTest {
    private static final ObjectTest instanceObj = new ObjectTest();

    private ObjectTest() {
    }

    public static ObjectTest getInstance() {
        return instanceObj;
    }

    public static void main(String[] args) {

        ObjectTest localObj = ObjectTest.getInstance();
    }
}

这是Singleton模式.

This is the Singleton pattern.

关于同一主题:

• 为什么会出现StackOverflowError
• java类中的循环依赖

• Why I'm getting StackOverflowError
• Circular dependency in java classes

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