List里将某字段相同的元素合并

import java.util.ArrayList;
import java.util.List;

class A {
    private String name;//姓名
    private int age;//年龄
    
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
}
public class Test4 {
    
    public static void main(String[] args) {
    List<A> oldList = new ArrayList<A>();//需要整合的List
    List<A> newList = new ArrayList<A>();//整合后的List
            A  aA = new A();
            aA.setName("a");
            aA.setAge(10);
            A  aB = new A();
            aB.setName("b");
            aB.setAge(20);
            A  aC = new A();
            aC.setName("c");
            aC.setAge(30);
            A  aD = new A();
            aD.setName("b");
            aD.setAge(40);
    
            oldList.add(aA);
            oldList.add(aB);
            oldList.add(aC);
            oldList.add(aD);
        for (A oldO : oldList) {
            boolean flag = true;//给整合后集合添加子元素标志，true：添加，false:不添加，其年龄相加
                for (A newO : newList) {
                    if (newO.getName(). equals(oldO.getName())) {//判断姓名是否相同
                        newO.setAge(newO.getAge()+oldO.getAge());//姓名相同时，年龄相加
                        flag = false;
                    }
                }
            if (flag) {
                newList.add(oldO);//给整合后集合添加子元素
            }
        }
        
        for (A a : newList) {//打印结果
            System.out.println(a.getName() + " : "+a.getAge());
        }
    }
}