Question

I was wondering if it is possible to check whether there is an instance of an object(my gui) open in Java and if so how I would be able to find it?

Answer 1

You can use following code if this question is for swing window like JFrame or JDialog,

    java.awt.Window win[] = java.awt.Window.getWindows();   
    for(int i=0;i<win.length;i++){   
        if (win[i].getName().equals("YourWindowName"))
          isOpen = true;
          break; 
    }   

For this ypu need to give name to your JFrame and if that matches with open windows it will set true and return.