请解释SVI与SV30概念,并说明区别。哪个值对判断曝气池活性污泥沉降性能更为直观?
1. class Pizza { 2. java.util.ArrayList toppings; 3. public final void addTopping(String topping) { 4. toppings.add(topping); 5. } 6. } 7. public class PepperoniPizza extends Pizza { 8. public void addTopping(String topping) { 9. System.out.println(”Cannot add Toppings”); 10. } 11. public static void main(String[] args) { 12. Pizza pizza = new PepperoniPizza(); 13. pizza.addTopping(”Mushrooms”); 14. } 15. } What is the result?() [" Compilation fails."," Cannot add Toppings"," The code runs with no output."," A NullPointerException is thrown in Line 4."]
铸造用生铁共有()个牌号。 ["2","4","6","8"]
在人类精神生活的最高领域,对最高层次和最核心观念的相信和信奉就是我们所说的:() ["信念","信仰","理想","思想"]
如何规避教育投资的风险?
浮顶油罐进行交接计量时的注意事项?