How to create an array of variable length in java?

#How to create an array of variable length in Java?

JAVA cannot define an array of variable length, either declare it as NULL or specify its length. If a collection of variable length is needed, we can use ArrayList to solve it.

1. First declare a collection list

ArrayList list = new ArrayList();

2. Then you can add data to it

list.add("123");
list.add("456");

3. You can use a loop to output all data

//遍历输出list数组
for(int i=0;i<list.size();i++){
   //get(index)方法，返回此列表中指定位置上的元素。
   System.out.print(list.get(i).toString()+" ");
}

4. Use the set method to replace elements

/* set(index,element)方法，用指定的元素替代此列表中指定位置上的元素。
 * index - 要替代的元素的索引
   element - 存储在指定位置上的元素
* */
list.set(2,"nihao");

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