Cannot override writeObject (Serializable model) method in AnyLogic

I have a model based on AnyLogic and tried to serialize it, but receive an StackOverflow error. As I understand the main reason is a circular agent reference. I can't find it however. I tried to override AnyLogic writeObject method in my function on the main agent to find the last serializing Agent.

try {
        FileOutputStream fos = new FileOutputStream("t.tmp");
        ObjectOutputStream out = new ObjectOutputStream(fos) {
            @Override
            protected void writeObjectOverride(Object obj) {
                System.out.println("Serializing: " + obj.getClass().getName() + " - " + obj);
                super.writeObjectOverride(obj);
            }
        };
        
        out.writeObject(this);
        out.close();
        System.out.println("Serialization completed successfully");
        
    } catch (IOException e) {
        System.err.println("Serialization error: " + e.getMessage());
        e.printStackTrace();
    }

I run my model in debug mode with breakpoints on the overriding method, but nothing happened. Model starts and when I call this function it executes an Anylogic writeObjectOverride method (i don't see any messages in console and my breakpoins didn't work) Whats happened?

Solution

From the documentation of writeObjectOverride

This method is called by trusted subclasses of ObjectOutputStream that constructed ObjectOutputStream using the protected no-arg constructor.

This does not fit your use case.

Instead, you should override replaceObject(Object). But don’t forget to invoke enableReplaceObject(true) in the constructor to enable this feature.

try(FileOutputStream fos = new FileOutputStream("t.tmp");
    ObjectOutputStream out = new ObjectOutputStream(fos) {
        { enableReplaceObject(true); }
        @Override
        protected Object replaceObject(Object obj) throws IOException {
            System.out.println("Serializing: " + obj.getClass().getName() + " - " + obj);
            return obj;
        }
      }) {

    out.writeObject(this);
    System.out.println("Serialization completed successfully");
} catch (IOException e) {
    System.err.println("Serialization error: " + e.getMessage());
    e.printStackTrace();
}