java反射机制如何通过类名获取对象！！急救！！

public abstract class AbstractFactory { public static AbstractFactory getInstance(String classname){ AbstractFactory abs=null; try { abs=(AbstractFactory) Class.forName(classname).newIn... public abstract class AbstractFactory { public static AbstractFactory getInstance(String classname){ AbstractFactory abs=null; try { abs=(AbstractFactory) Class.forName(classname).newInstance(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } return abs; } abstract Connection getConnection(); abstract Statement getStatement(); } 运行显示abs的值是空的，如果我加上abs.getConnection().createConnection();也不会输出，求指教，哪里错了啊。没钱了，只能悬赏5个了，，