DeleteTree.java

public class DeleteTree {
	// to delete a binary tree, we need to set all the node objects to null then
	// garbage collection will take care of rest of the things
	//do the post order traversal and set the node to null
	public static Node deleteTree(Node root) {
		if (root != null) {
			deleteTree(root.left);
			deleteTree(root.right);	
			System.out.println("Deleting Node:" + root.data);
			root=null;
			return root;
		}
		return null;
	}
	
	public static void main(String[] args) {
		Node root = new Node(1);
		root.left = new Node(2);
		root.right = new Node(3);
		root.left.left = new Node(4);
		root.left.right = new Node(5);
		
		deleteTree(root);
	}
}

class Node {
	int data;
	Node left;
	Node right;

	public Node(int data) {
		this.data = data;
	}
}