Simple OOP question- Creating objects

[TSSF44]

I am very new to programming in Java. Can anyone take this code and add comments ( // ) so I can better understand what each line does?

 
class TestNumber                                            // creates Class  named TestNumber
{
   public static void main(String[] args)                // This is the main method
   {
      Number n1 = new Number(10);                   // To my understanding, this will create an object n1  and assign 10 to that object?
      Number n2 = new Number(20);
      Number n3 = n1.add(n2);                            
      System.out.println("n3 = " + n3.toString());
   }
}
//================================================
class Number
{
   private int x;
   //----------------------------------
   public Number(int xx)
   {
      x = xx;
   }
   //----------------------------------
   public Number add(Number r)
   {
      return new Number(x + r.x);
   }
   //----------------------------------
   public String toString()
   {
      return "" + x;      // return value in x as String
   }
}

[newbie]

 
	/*
	 * [url=http://docs.oracle.com/javase/tutorial/java/concepts/class.html]What Is a Class? (The Java™ Tutorials > Learning the Java Language > Object-Oriented Programming Concepts)[/url]
	 */
	class Number {
		private int x;
 
		/*
		 * [url=http://docs.oracle.com/javase/tutorial/java/javaOO/constructors.html]Providing Constructors for Your Classes (The Java™ Tutorials > Learning the Java Language > Classes and Objects)[/url] 
		 */
		public Number(int xx) {
			x = xx;
		}
 
		/*
		 * [url=http://docs.oracle.com/javase/tutorial/java/javaOO/methods.html]Defining Methods (The Java™ Tutorials > Learning the Java Language > Classes and Objects)[/url]
		 */
		public Number add(Number r) {
			return new Number(x + r.x);
		}
 
		/*
		 * [url=http://javaexamplebyme.blogspot.co.uk/2012/07/how-to-override-tostring-method-in-java.html]javaexample: How to override toString() Method in java[/url]
		 * @see java.lang.Object#toString()
		 */
		public String toString() {
			return "" + x; // return value in x as String
		}
	}

Always happy to help

[Whitescars]

I am very new to programming in Java. Can anyone take this code and add comments ( // ) so I can better understand what each line does?

 
class TestNumber                                            // creates Class  named TestNumber
{
   public static void main(String[] args)                // This is the main method
   {
      Number n1 = new Number(10);                   // To my understanding, this will create an object n1  and assign 10 to that object? (yes, type of the object is Number)
      Number n2 = new Number(20);                   // Samething
      Number n3 = n1.add(n2);                          // This will create object and assign return value from add method.  
      System.out.println("n3 = " + n3.toString());  // this line will print n3 to console
   }
}
//================================================
class Number // Class definition
{
   private int x; // Class variable called x
   //----------------------------------
   public Number(int xx) // Constructor
   {
      x = xx; // While creating number objects, you need to send integer values as you do above, so this line will assign passed number to class variable x, so you can use x in other methods.
   }
   //----------------------------------
   public Number add(Number r) // Defining method add
   {
      return new Number(x + r.x); // Creates a new Number 
   }
   //----------------------------------
   public String toString() // This is class method overriding, you describe how toString method of Number class will display the number here.
   {
      return "" + x;      // return value in x as String
   }
}

Here you go