Adding objects to a fixed Array in Java -

up till i've been using arraylists. i've used arrays once used differently how i'm suppose now. have class called member , looks this:

public class member {     private string firstname;     private string lastname;     private int monthjoined;     private int yearjoined; } 

of course class has accessor/ mutator methods , constructors below.

now have make class called club can hold fixed number of members stored in member[] array. (the fixed number can number) @ point i'm wondering variable like. class need method titled public void join(member member) adds member club, new members added first null index in array.

i know how work arraylist not array. given class club variable , method like?

i discourage using array when arraylist job better. in general, in java, collections (e.g. arraylist) preferred array, unless specific circumstances dictate otherwise.

the main disadvantage of arrays size must fixed @ time of initialization , remains long reference array remains available. thus, if club may contain 1000 members in next 5 years, need allocate 1000 members right now. moment 1001st member joins, have allocate new , improved array, copy existing members , use new array. , more done arraylist transparently.

having said that, using array should straightforward:

class club {     //thread unsafe      private member[] members;     private int ncurrentmembers = 0;      club(int initialcapacity) {         //validate initialcapacity         members = new member[initialcapacity];     }      public boolean join(member m) {         //validate m         if (ncurrentmembers == members.length) {             members = arrays.copyof(members, members.length + 100);         }         members[ncurrentmembers++] = m;         return true;     }     public boolean leave(member m) {         // homework :-)         return true;     } }