Disposing a jframe, and freeing up memory

Question

Greetings,
I hope this is the proper forum for memory issues.
I have an enterprise database reporting desktop application that I am developing. The GUI application reports on a huge set of data that results in the app taking up to 125 MB worth of memory when fully loaded. There are moments in using the application that all of the data will need to be refreshed entirely, and the JFrame that reports it be reloaded in the process.
I am wondering how to dispose the JFrame and release all of the data associated with it. I use NetBeans to develop my GUI, and so all of the data that is needed for the JFrame is a class variable of the JFrame (so the data can be accessed as it is needed). But, when the frame is disposed, I no longer need anything associated with the JFrame that gets disposed. The Javadoc for Window.dispose() seems to imply that not all of the resources will be released and GC'd when you call dispose, because it says "The Window and its subcomponents can be made displayable again by rebuilding the native resources with a subsequent call to pack or show." which to me says that the data is being remembered and not collected by the GC.
Anyone have any tips for GUIs and memory management? It seems like any GUI app could get pretty large pretty fast if there's no way to release the data associated with the GUI.
Here's the code I've tested that doesn't seem to be releasing the memory (stress tests of closing and re-opening the window multiple times shows the java.exe process eating more and more memory):
    public void reset(){
        this.dispose();
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new PartsDashboard(partNum, dateFrom, dateTo);
        try{
            this.finalize();
        } catch (Throwable t){
            t.printStackTrace();
    }Thanks in advance.

Answer 1

Three things you can always count on in life: Death, Taxes, and AndrewThompson64 telling people to post an SSCCE. =)
Just poking fun.
Anyways, this problem has gone from probably-should-deal-with-soon to critical issue. Here is the SSCCE to illustrate the problem. NOTE: My client is using Windows and I am using Windows, so how this acts on Linux/Mac isn't important to me. Also, a few of my client's machines are not well equipped (512 MB RAM), so they have agreed to up their hardware a bit.
But the big problem, on my end, is that disposed windows DO NOT free up resources once disposed. My program is very data-heavy. I have considered grabbing less data from the database but this would mean the program would have to go to the database more often. The ultimate dilemma of time vs space, essentially.
To explain the SSCCE: There is a main window with a button. If you click the button, it launches another window with a String array that is 500,000 items large (to simulate a lot of data), and a JList to view those strings. Closing the data-heavy child window does not free up the memory that it uses, and if you launch a bunch of the child windows in the same program instance (close each child before launching a new one) then you will see the amount of memory piling up.
Am I doing something wrong? Has anyone else experienced similar problems? Does anyone have suggestions? Thank you.
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
* @author Ryan
public class MemoryLeak {
    public static void main(String[] args) {
        // Launch Base Frame
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new BaseFrame().setVisible(true);
class BaseFrame extends JFrame{
    public BaseFrame() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setPreferredSize(new Dimension(300,300));
        JPanel panel = new JPanel();
        panel.setLayout(new FlowLayout(FlowLayout.CENTER, 150, 5));
        JButton button = new JButton("Launch Data-Heavy Child");
        // JButton will launch Child Frame
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                java.awt.EventQueue.invokeLater(new Runnable() {
                    public void run() {
                        // Notice no references to ChildFrame, period.
                        new ChildFrame().setVisible(true);
        panel.add(button);
        add(panel);
        pack();
class ChildFrame extends JFrame{
    public ChildFrame() {
        setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        setPreferredSize(new Dimension(300,600));
        JPanel panel = new JPanel();
        panel.setLayout(new FlowLayout());
        // Simulate lots of data.
        String[] dataArr = new String[500000];
        for(int i = 0; i < dataArr.length; i++) {
            dataArr[i] = "This is # " + i;
        // Something to display the data.
        JList list = new JList(dataArr);
        JScrollPane scrollPane = new JScrollPane(list);
        scrollPane.setPreferredSize(new Dimension(200, 550));
        panel.add(scrollPane);
        add(panel);
        pack();
}