Customer ArrayList Class amending Specific Element in Java -

how change specific variable @ specific point in custom arraylist? have created arraylist class , need adjust variable within list, cannot seem figure how achieve it. have searched answer nothing seems specific problem.

the code super class is:

public class parcel extends jpanel {     protected int idnum;     protected double charge;     protected char zone;     protected imageicon i;     protected static arraylist<parcel> parcellist;     protected static parcellist newparcel = new parcellist();  public parcel(int id, char z)  {     this.idnum = id;     this.zone = z; } 

and code list is...

public class parcellist extends parcel {  parcellist() {     parcellist = new arraylist<parcel>(); }  public void addbox(int id, char z, int w, int l, int h) {     parcellist.add(new box(id,z,w,l,h)); } 

what looking change imageicon example, change imageicon of 5th element in list of list contains many different instances of box differing images. , removing element.

is possible current way have set code up?

never minding seems redundancy in code, 1 way use newparcel.get(index), modify box using setter methods, newparcel.set(index, newbox)