hackjutsu

public class PetRepository implements Container {
  private class NameIterator implements Iterator {
    int index = 0;

    @Override
    public boolean hasNext() {
      return index < pets.length;
    }

    @Override

hackjutsu

public interface Iterator {
  boolean hasNext();
  Object next();
}

public interface Container {
  Iterator getIterator();
}

hackjutsu

public interface Strategy {
   public int doOperation(int num1, int num2);
}

public class OperationAdd implements Strategy{
   @Override
   public int doOperation(int num1, int num2) {
      return num1 + num2;
   }
}

hackjutsu

public enum Elvis {
  INSTANCE;
  public void someMethod() {...}
}

hackjutsu

public class Elvis {
  private static final Elvis INSTANCE = new Elvis();
  
  public static Elvis getInstance() {
    return INSTANCE;
  }
  
  private Elvis() {...}
}

hackjutsu

public class Something {
  private static class LazyHolder {
    private static final Something INSTANCE = new Something();
  }

  public static Something getInstance() {
    return LazyHolder.INSTANCE;
  }
  
  private Something() {}

hackjutsu

class Foo {
  private Helper helper = null;
  public Helper getHelper() {
    if (helper == null) {
      synchronized(this) {
        if (helper == null) {
          helper = new Helper();
        }
      }
    }

hackjutsu

public class Singleton {
  private volatile static Singleton uniqueInstance;    
    
  public static Singleton getInstance() {
    if (uniqueInstance == null) {
      synchronized (Singleton.class) {
        if (uniqueInstance == null) {
          uniqueInstance = new Singleton();
        }
      }

hackjutsu

sudo snap install snapcraft || brew install snapcraft
snapcraft login
snapcraft register lepton
snapcraft push --release stable Lepton_1.6.2_amd64.snap

hackjutsu