Changed package naming across all examples.

null-object/src/main/java/com/iluwatar/nullobject/NodeImpl.java

@@ -0,0 +1,50 @@
+package com.iluwatar.nullobject;
+
+/**
+ * 
+ * Implementation for binary tree's normal nodes.
+ *
+ */
+public class NodeImpl implements Node {
+
+	private final String name;
+	private final Node left;
+	private final Node right;
+	
+	public NodeImpl(String name, Node left, Node right) {
+		this.name = name;
+		this.left = left;
+		this.right = right;
+	}
+	
+	@Override
+	public int getTreeSize() {
+		return 1 + left.getTreeSize() + right.getTreeSize();
+	}
+
+	@Override
+	public Node getLeft() {
+		return left;
+	}
+
+	@Override
+	public Node getRight() {
+		return right;
+	}
+
+	@Override
+	public String getName() {
+		return name;
+	}
+
+	@Override
+	public void walk() {
+		System.out.println(name);
+		if (left.getTreeSize() > 0) {
+			left.walk();
+		}
+		if (right.getTreeSize() > 0) {
+			right.walk();
+		}
+	}
+}