Java | Фишки и трюки

public class Quest {
    public static void main(String[] args) {
        System.out.println(isEqual(1, 1));
    }

    private static boolean isEqual(int i, int j) {
        return (i == j) ? null : false;
    }
}

public static void main(String[] args) {}

public class Quest {
    public static void main(String[] args) {
        System.out.println(true &! false);
    }
}

public class MyUI extends UI {
    @Override
    protected void init(VaadinRequest request) {
        Button button = new Button("Click me");
        button.addClickListener(e -> Notification.show("Button clicked"));

        setContent(button);
    }
}

VerticalLayout layout = new VerticalLayout();
layout.addComponent(new Label("Hello, Vaadin!"));
layout.addComponent(new Button("Click me"));
setContent(layout);

System.out.println(2 ^ 3);

public class Quest {
    public static void main(String[] args) {
        System.out.println(cond(1) && cond(2));
    }

    private static boolean cond(int i) {
        try {
            return false;
        } finally {
            System.out.print(i);
        }
    }
}

boolean f = false;
System.out.println(f = f ^ true);

public enum Day {
    MONDAY("понедельник"),
    TUESDAY("вторник"),
    WEDNESDAY("среда"),
    THURSDAY("четверг"),
    FRIDAY("пятница"),
    SATURDAY("суббота"),
    SUNDAY("воскресенье");
    
    Day(String value) {
        this.value = value;
    }
    
    String value;
    
    public String getValue() {
        return value;
    }

}

public class EnumClass {
    public static void main(String[] args) {
        System.out.println(message(Day.FRIDAY));
    }
    public static String message(Day day) {
        return "Это " + day.getValue();
        // Это пятница
    }
}