Display file(s) name and select it under t

I managed to come this far using stackoverflow examples, JTree displays all the system drives and folders, wanted to display all the corresponding files from the folder as well, got all the file names in a loop need to add them, that's where I got stuck!

Please give me direction to add the files under the folder, Thanks!

CODE:

public class viewGui extends JFrame {

    private FileSystemView fileSystemView;
    private Desktop desktop;
    private static final long serialVersionUID = 1083130296343096642L;
    public static JTree tree;
    private DefaultTreeModel treeModel;
    private JTable table;
    private ListSelectionListener listSelectionListener;

    private static final LayoutManager H = new GridLayout(1, 0);
    private static final LayoutManager V = new GridLayout(0, 1);

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    viewGui mainWindow = new viewGui();
                    mainWindow.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public viewGui() {

        fileSystemView = FileSystemView.getFileSystemView();
        desktop = Desktop.getDesktop();

        this.setTitle("Student Record Book");
        getContentPane().setLayout(H);
        getContentPane().setLayout(V);
        this.setPreferredSize(new Dimension(1200, 800));
        this.setExtendedState(NORMAL);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.getContentPane().setLayout(null);
        this.setResizable(true);

        DefaultMutableTreeNode root = new DefaultMutableTreeNode();
        treeModel = new DefaultTreeModel(root);

        TreeSelectionListener treeSelectionListener = new TreeSelectionListener() {
            public void valueChanged(TreeSelectionEvent tse){
                DefaultMutableTreeNode node = (DefaultMutableTreeNode)tse.getPath().getLastPathComponent();
                System.out.println("Node: "+node);
                showChildren(node);
            }
        };

        File[] roots = fileSystemView.getRoots();
        for (File fileSystemRoot : roots) {
            DefaultMutableTreeNode node = new DefaultMutableTreeNode(fileSystemRoot);
            root.add( node );
            File[] files = fileSystemView.getFiles(fileSystemRoot, true);
            for (File file : files) {
                if (file.isDirectory()) {
                    node.add(new DefaultMutableTreeNode(file));
                }
            }
        }

        tree = new JTree(treeModel);
        tree.setBounds(10, 11, 387, 740);
        tree.setRootVisible(false);
        tree.addTreeSelectionListener(treeSelectionListener);
        tree.expandRow(0);
        JScrollPane treeScroll = new JScrollPane(tree);

        tree.setVisibleRowCount(15);

        Dimension preferredSize = treeScroll.getPreferredSize();
        Dimension widePreferred = new Dimension(200,(int)preferredSize.getHeight());
        treeScroll.setPreferredSize( widePreferred );

        this.setLayout(H);
        this.validate();
        this.add(treeScroll, BorderLayout.WEST);
        this.pack();
        this.setLocationRelativeTo(null);
        this.setVisible(true);

        table = new JTable();
        table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        table.setAutoCreateRowSorter(true);
        table.setShowVerticalLines(false);

        listSelectionListener = new ListSelectionListener() {
            @Override
            public void valueChanged(ListSelectionEvent lse) {
                int row = table.getSelectionModel().getLeadSelectionIndex();
            }
        };

        table.getSelectionModel().addListSelectionListener(listSelectionListener);
        JScrollPane tableScroll = new JScrollPane(table);
        Dimension d = tableScroll.getPreferredSize();
        tableScroll.setPreferredSize(new Dimension((int)d.getWidth(), (int)d.getHeight()/2));
        getContentPane().add(tableScroll, BorderLayout.CENTER);


    }

    private void showChildren(final DefaultMutableTreeNode node) {
        tree.setEnabled(false);

        SwingWorker<Void, File> worker = new SwingWorker<Void, File>() {
            @Override
            public Void doInBackground() {
                File file = (File) node.getUserObject();
                if (file.isDirectory()) {
                    File[] files = fileSystemView.getFiles(file, true); //!!
                    if (node.isLeaf()) {
                        for (File child : files) {

                            System.out.println("child:"+child);
                            if (child.isDirectory()) {
                                publish(child);
                                //Need to add the file names under the folder
                            }
                        }
                    }
                }
                return null;
            }

            @Override
            protected void process(List<File> chunks) {
                for (File child : chunks) {
                    node.add(new DefaultMutableTreeNode(child));
                    if (child.isDirectory()){

                    }
                }
            }

            @Override
            protected void done() {
                tree.setEnabled(true);
            }
        };
        worker.execute();
    }
}

Don't add all the file names in a loop. Instead, create a FileTreeModel that implements TreeModel, as shown here. The implementation simply invokes the File method listFiles() in getChild() and getIndexOfChild(). Then you can create a tree and expand any desired row; use setSelectionPath() as shown here.

TreeModel model = new FileTreeModel(new File(System.getProperty("user.dir")));
JTree tree = new JTree(model);
tree.expandRow(0);

I get only the c:\; please give me directions to get all the system drives, etc.

You can get a list of filesystem roots with File.listRoots(), as shown in Find all drive letters in Java, or FileSystemView#getRoots(), as shown in File Browser GUI.