Java Binary Tree Boundary Traversal

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public class JavaBinaryBoundaryTraversal {

	public static class TreeNode {
		int data;
		TreeNode left;
		TreeNode right;

		TreeNode(int data) {
			this.data = data;
		}
	}

	public static void boundaryLevelTraversal(TreeNode root) {
		System.out.print(root.data + " ");
		printLeftEdgeNodes(root.left);
		printLeafNodes(root);
		printRightBottomUp(root.right);

	}

	private static void printLeafNodes(TreeNode root) {
		if (root == null)
			return;

		if (root.left == null && root.right == null) {
			System.out.print(root.data + " ");
			return;
		}
		printLeafNodes(root.left);
		printLeafNodes(root.right);
	}

	private static void printRightBottomUp(TreeNode root) {
		if (root == null)
			return;

		if (root.left == null && root.right == null) {
			return;
		}

		if (root.right != null) {
			printRightBottomUp(root.right);
		} else if (root.left != null) {
			printRightBottomUp(root.left);
		}

		System.out.print(root.data + " ");
	}

	private static void printLeftEdgeNodes(TreeNode root) {
		if (root == null)
			return;

		if (root.left == null && root.right == null)
			return;

		System.out.print(root.data + " ");

		if (root.left == null) {
			printLeftEdgeNodes(root.right);
		} else {
			printLeftEdgeNodes(root.left);
		}

	}

	public static void main(String[] args) {
		TreeNode rootNode = createBinaryTree();
		System.out.println("Boundary traversal of binary tree will be:");
		boundaryLevelTraversal(rootNode);
	}

	public static TreeNode createBinaryTree() {

		TreeNode rootNode = new TreeNode(40);
		TreeNode node20 = new TreeNode(20);
		TreeNode node10 = new TreeNode(10);
		TreeNode node30 = new TreeNode(30);
		TreeNode node60 = new TreeNode(60);
		TreeNode node50 = new TreeNode(50);
		TreeNode node70 = new TreeNode(70);
		TreeNode node5 = new TreeNode(5);
		TreeNode node45 = new TreeNode(45);
		TreeNode node55 = new TreeNode(55);

		rootNode.left = node20;
		rootNode.right = node60;

		node20.left = node10;
		node20.right = node30;

		node60.left = node50;
		node60.right = node70;

		node10.right = node5;
		node5.right = node45;

		node50.right = node55;
		return rootNode;
	}
}
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