Refactoring :: Rule of Three

step_01.java

private void askQuestion() {
    if (currentCategory() == "Pop")
        System.out.println(pop.removeFirst());
    if (currentCategory() == "Science")
        System.out.println(science.removeFirst());
    if (currentCategory() == "Sports")
        System.out.println(sport.removeFirst());
    if (currentCategory() == "Rock")
        System.out.println(rock.removeFirst());
}

step_02.java

private void askQuestion() {
    if (currentCategory() == "Pop") {
        Object message = pop.removeFirst();
        System.out.println(message);
    }
    if (currentCategory() == "Science") {
        Object message = science.removeFirst();
        System.out.println(message);
    }
    if (currentCategory() == "Sports") {
        Object message = sport.removeFirst();
        System.out.println(message);
    }
    if (currentCategory() == "Rock") {
        Object message = rock.removeFirst();
        System.out.println(message);
    }
}

step_03.java

private void askQuestion() {
    if (currentCategory() == "Pop") {
        Object message = pop.removeFirst();
        showMessageOnConsole(message);
    }
    if (currentCategory() == "Science") {
        Object message = science.removeFirst();
        showMessageOnConsole(message);
    }
    if (currentCategory() == "Sports") {
        Object message = sport.removeFirst();
        showMessageOnConsole(message);
    }
    if (currentCategory() == "Rock") {
        Object message = rock.removeFirst();
        showMessageOnConsole(message);
    }
}

step_04.java

private void askQuestion() {
    if (currentCategory() == "Pop") {
        showMessageOnConsole(pop.removeFirst());
    }
    if (currentCategory() == "Science") {
        showMessageOnConsole(science.removeFirst());
    }
    if (currentCategory() == "Sports") {
        showMessageOnConsole(sport.removeFirst());
    }
    if (currentCategory() == "Rock") {
        showMessageOnConsole(rock.removeFirst());
    }
}