Question

我有一个班级，我有大约10个ArrayList和我新手到垃圾收集我学会了从内存释放对象可以三种方式完成... 使用匿名对象或使其为空.....但在我的行动后，我无法使它无null在jsp页面中没有显示...这是我的代码......

class myAction extends ActionSupport{
private ArrayList<Object> ShopList1=new  ArrayList<Object>();
private ArrayList<Object> ShopList2=new  ArrayList<Object>();
private ArrayList<Object> ShopList3=new  ArrayList<Object>();
private ArrayList<Object> ShopList4=new  ArrayList<Object>();
private ArrayList<Object> ShopList5=new  ArrayList<Object>();
public execute{

ShopList1.put("Adding 20 Object");
ShopList2.put("Adding 20 Object");
ShopList3.put("Adding 20 Object");
ShopList4.put("Adding 20 Object");

setShopList1(ShopList1);
setShopList2(ShopList2);
setShopList3(ShopList3);
setShopList4(ShopList4);
setShopList5(ShopList5);
//If i make All arrayList Null the result does not show up in JSP...
return SUCCESS;
}

public ArrayList<Object> getShopList1() {
            return ShopList1;
        }
        public void setShopList1(ArrayList<Object> shopList1) {
            ShopList1 = shopList1;
        }
        public ArrayList<Object> getShopList2() {
            return ShopList2;
        }
        public void setShopList2(ArrayList<Object> shopList2) {
            ShopList2 = shopList2;
        }
        public ArrayList<Object> getShopList3() {
            return ShopList3;
        }
        public void setShopList3(ArrayList<Object> shopList3) {
            ShopList3 = shopList3;
        }
        public ArrayList<Object> getShopList4() {
            return ShopList4;
        }
        public void setShopList4(ArrayList<Object> shopList4) {
            ShopList4 = shopList4;
        }
        public ArrayList<Object> getShopList5() {
            return ShopList5;
        }
        public void setShopList5(ArrayList<Object> shopList5) {
            ShopList5 = shopList5;
        }

}

所以我的问题是我什么时候发布arrayList或者JVM是否为我做了。

Answer 1

如果要从列表中删除对象，可以使用 ArrayList.remove（object）。

您不能强制垃圾收集器从堆中垃圾。通常，它没有引用时自动符合垃圾收集器

如何使用Struts2从Java中释放ArrayList

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