Added comments for the visitor example.

visitor/src/main/java/com/iluwatar/App.java

@@ -1,5 +1,12 @@
 package com.iluwatar;
 
+/**
+ * 
+ * Visitor pattern defines mechanism to apply operations
+ * (UnitVisitor) on nodes (Unit) in hierarchy. New operations 
+ * can be added without altering the node interface.
+ *
+ */
 public class App 
 {
     public static void main( String[] args )

visitor/src/main/java/com/iluwatar/Unit.java

@@ -1,5 +1,10 @@
 package com.iluwatar;
 
+/**
+ *
+ * Interface for the nodes in hierarchy.
+ * 
+ */
 public abstract class Unit {
 
 	private Unit[] children;

visitor/src/main/java/com/iluwatar/UnitVisitor.java

@@ -1,5 +1,10 @@
 package com.iluwatar;
 
+/**
+ * 
+ * Visitor interface.
+ *
+ */
 public interface UnitVisitor {
 
 	void visitSoldier(Soldier soldier);