Can someone tell me how to test Linear List?

[Ezz]

Hi can someone tell me what is wrong with this? I keep getting error reading class, interface, or enum expected

public static void main(String[] args)
{
LinearList list = new ArrayLinearList();
letters.addLast("g");
letters.addLast("b");
letters.addLast("b");
letters.addLast("c");
letters.addLast("d");
letters.addLast("c");

letters.add(2,a);
letters.output();
letters.add(indexOf(c), k);
letters.output();
letters.remove(indexOf(b) + 1);
letters.output();
letters.remove(size() - 2);
letters.output();
}