garbage collector for JFrame's object

Question

import javax.swing.*;

public class Main
{
    public Main()
    {
        JFrame jf = new JFrame(\"Demo\");
        jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          


        

Answer 1

When a JFrame is created, it registers itself in some internal Swing data structures which allow it to receive events like mouse clicks. This means there is a reference to your object lurking somewhere until you tell Swing to get rid of the window using dispose().