为什么在方法参数中使用Final

当我编写android时,我遇到了以下事情

@Override
    public View getView(final int position, View convertView, ViewGroup parent) {

        convertView = _inflater.inflate(R.layout.abstract_list_row_item, null);
        move.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {  
                    // if btn is clcked then data is changed an we need to refresh framents
                    MainAppDataController.getInstance().setIsDataChanged(true);
                    callWhiteListDB = new CallWhiteListDB(_context);
                    callWhiteListDB.openToWrite();
                    callWhiteListDB.insert(allContacts.get(position).name, allContacts.get(position).number);
                    callWhiteListDB.close();

                    callBlackListDB = new CallBlackListDB(_context);
                    callBlackListDB.openToWrite();
                    callBlackListDB.deleteSingleItem(allContacts.get(position).dbId);
                    callBlackListDB.close();
                    populateList(position);
                    notifyListView(view);
                }
            });
        return convertView;

在上面的示例中,getView()方法有像int position,View convertView,ViewGroup parent这样的参数.我的观察是在我开始使用位置变量时onclick(),Eclipse抛出编译错误并要求将位置作为final.我为什么要把它作为最终版？AFAIK final用于常量.