In Java, a JTree is a basic GUI component used to display hierarchical data, such as a file system or a tree structure. Here's a basic example of how to create and use a JTree:

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;

public class TreeExample extends JFrame {

    public TreeExample() {
        super("JTree Example");

        // Create the root node and add child nodes to it
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");
        DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("Node 1");
        DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("Node 2");
        root.add(node1);
        root.add(node2);

        // Create the tree and add it to a scroll pane
        JTree tree = new JTree(root);
        JScrollPane scrollPane = new JScrollPane(tree);

        // Add the scroll pane to a panel and add the panel to the frame
        JPanel panel = new JPanel();
        panel.add(scrollPane);
        add(panel);

        // Set the size, location and visibility of the frame
        pack();
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);
    }

    public static void main(String[] args) {
        new TreeExample();
    }
}

In this example, we create a JTree by creating a DefaultMutableTreeNode to represent the root of the tree, and then adding child nodes to it. We then create the JTree using the root node and add it to a JScrollPane.

We add the JScrollPane to a JPanel and add the panel to the JFrame. When you run this example, a window will appear with a tree view of the nodes we created. You can expand and collapse the nodes by clicking on them.