Save state of object in IntelliJ debug?

To expand on Josep's answer, your best bet is to import Google's Gson library into your project and run:

Gson gson = new Gson();
gson.toJson(yourObject);

Then copy the value from the result.

Here's an example on IntelliJ IDEA:

As a very simple solution you can use the Fully Expand Tree Node action for objects in Variables or Watches views. This action is bound to Numpad * key (*) by default and opens the whole object tree. Then you select all the elements of opened object tree with shift and copy them to clipboard.