Question

I have the following logic to remove inactive users in the system, since we cannot remove a row while iterating on the list. Is there a better way to handle this?

List<User> users = new ArrayList<User>();
List<User> removeUsers = new ArrayList<User>();

for (User user : users) {
  if (!user.isActive()) {
      removeUsers.add(user);
  }
}

users.removeAll(removeUsers);

Answer 1

That’s a perfectly fine way to do it IMHO.

Other ways that I might do it, use indexing and remove as you loop through in reverse.

for (int i = users.size()-1; i >= 0; i--)
{
    if (!users.get(i).isActive())
    {
        users.remove(i);
    }
}

Or create a new list of the items to be kept and replace it with the old list.

List<User> newUsers = new ArrayList<User>();
for (User user : users)
{
    if (user.isActive())
    {
        newUsers.add(user);
    }
}
users = newUsers;

Can’t think of any others at the moment.