該列表可能包含整數和字符串值。在這種情況下,我應該創建對象列表嗎? List<Object> list = new ArrayList<Object>();
如何使用列表的整數條目執行簡單的算術運算? list.add(1);
list.add("ok");
list.add(2);
Integer a = list.get(0) - list.get(2); // does not w
如何評估以下表達式? Student類: public class Student
{
private Integer id;
// few fields here
public Integer getId()
{
return id;
}
public void setId(Integer id)
{
見這段代碼: import java.util.*;
public class Temp{
public static void main(String[] args){
List<int[]> list1 = new ArrayList<int[]>(); //WORKS!
List<double[]> list2 = new ArrayList<double
我遇到了一個非常奇怪的行爲,後來found to be a part of java specs。讓我把相關的代碼從上述發佈 Integer a = 1000, b = 1000;
System.out.println(a == b); //Prints false
Integer c = 100, d = 100;
System.out.println(c