对于上面解释的问题，此解决方案可能会对您有所帮助

private static boolean search(Object object, Object searchingObject) {
    List<?> al = (ArrayList) object;
    for (int index = 0; index < al.size(); index++) {
        if (al.get(index) instanceof List) {
             if(search(al.get(index), searchingObject)) {
                 return true;
             }
        } else {
            Iterator<Object> itr = (Iterator<Object>) al.iterator();
            Object o;
            while (itr.hasNext()) {
                o = itr.next();
                if (o.equals(searchingObject)) {
                    return true;
                }
            }
        }
    }
    return false;
}

abve代码的主要方法

public static void main(String[] args) {
    ArrayList<ArrayList> o = new ArrayList<>();
    ArrayList<Integer> al = new ArrayList<>();
    ArrayList<ArrayList<Integer>> o1 = new ArrayList<>();
    al.add(2);
    al.add(3);
    al.add(4);
    o1.add(al);
    o.add(o1);
    Integer i = 4;//Object which has to be searched
    System.out.println(search(o,i));//returning true
}