@Override
    public boolean init(List<String> argumentList, DebuggerVirtualMachine dvm) {
        breakpointLinesToSet = new ArrayList<String>();
        breakableLineNumbers = new ArrayList<String>();

        for (int i = 1; i < dvm.getSourceLinesSize(); i++) {
            if (dvm.isBreakableLine(i)) {
                breakableLineNumbers.add(new Integer(i).toString());
            }
        }
        for (String arg : argumentList) {
            if (!breakableLineNumbers.contains(arg)) {
                UserInterface.println(
                        arg + " is not a valid breakpoint line number.");
                UserInterface.print("Breakpoints can be set on lines: ");
                for (String lineNum : breakableLineNumbers) {
                    UserInterface.print(lineNum + " ");
                }
                UserInterface.println("\n");
                return false;
            }
            breakpointLinesToSet.add(arg);
        }
        return true;
    }