Let us start with a simple root with just 2 nodes: package And then we can recursively add nodes to that root. This class has a handy add() method which takes in an instance of MutableTreeNode. This class is provided in the Swing API and we can use it to represent our nodes. We will be using the DefaultMutableTreeNode class to represent our node.

Swing API provides an implementation of this interface in the form of DefaultMutableTreeNode class. The interface MutableTreeNode extends this interface which represents a mutable node. The node is represented in Swing API as TreeNode which is an interface. Let us say we want to display the list of vegetables and fruits hierarchically. Developing a Simple JTree: Let us now attempt to build a simple JTree. Expanding a node displays the children and collapsing hides them. The nodes with children are displayed with a different visual indicator along with a visual 'handle' which can be used to expand or collapse that node. The leaf node is displayed with a different visual indicator. If a node doesn't have any children node, it is called a leaf node. These children nodes themselves can have further children nodes. A JTree has a 'root node' which is the top-most parent for all nodes in the tree. Introduction to JTree: JTree is a Swing component with which we can display hierarchical data.

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