Class Communication Walkthrough

Step through main as it orchestrates a card game. Notice main never does any card work itself — it just connects the right objects.

Step 0 of 6

Click Start to walk through how Main, Deck, Hand, and Card all collaborate.

  // MainApp.java
  public class MainApp {
      public static void main(String[] args) {
          Deck deck = new Deck();
          Hand hand1 = new Hand();
          // deal 5 cards
          for(int i = 0; i < 5; i++) {
              Card card = deck.deal();
              hand1.deal(card);
          }
          int handValue = hand1.getValue();
          System.out.println("Hand value: " + handValue);
      }
  }

Heap — live objects

Console

The big idea: main doesn't shuffle anything. It doesn't add up card values. It doesn't track what's left in the deck. Each class does its own job. main is just the conductor — it tells Deck to deal, hands the result to Hand, asks Hand for the total. This is what people mean by "separation of concerns."

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