列出Java中的对象

Question

I'm new to Java so my apologies if this is a stupid question. I'm looking for a way to list all the objects in a class from another class so I don't need to add them to a list as they are created. The idea is then I would be able to use eg for(objects : class) {//do something} but I can't find a way to get a list of them.

Does anyone know of a way to do this if it is possible?

Thank you very much.

Answer 1

Java does not support itself. But you can implement your own mechanism. Below is sample code. I hope this is not requirement for any production level code. Because below code will hold references to all the objects and they won't be eligible for garbage collection and may lead to memory leak for high volumes of instances

import java.util.*;
public class HelloWorld
{
  private static final List<HelloWorld> list = new ArrayList<>();

  public HelloWorld(){
    list.add(this);
  }

  public static void main(String[] args)
  {
    HelloWorld object = new HelloWorld();
    System.out.print(list.size());
  }
}