一个关于继承和多态的问题（提问篇）
这个问题是我自己的一个盲点问题，因为当我看到以下的代码以及选项的时候，我做出了错误的选择。后来，我知道了原因所在，但是我想应该会有很多不同的解释，特将问题列示如下。首先，先看一下代码：<div style="padding-right: 5.4pt; padding-left: 5.4pt; background: #e6e6e6; padding-bottom: 4px; width: 98%; padding-top: 4px;"> http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedBlock.gifpublic class Test http://www.agoit.com/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif public static void main(String[] args) http://www.agoit.com/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif A ref1 = new C();
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif B ref2 = (B) ref1;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif System.out.println(ref2.g());
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockEnd.gif}
http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedBlock.gifclass A http://www.agoit.com/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif private int f() http://www.agoit.com/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return 0;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif public int g() http://www.agoit.com/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return 3;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockEnd.gif}
http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedBlock.gifclass B extends A http://www.agoit.com/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif private int f() http://www.agoit.com/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return 1;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif public int g() http://www.agoit.com/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return f();
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockEnd.gif}
http://www.agoit.com/Images/OutliningIndicators/None.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedBlock.gifclass C extends B http://www.agoit.com/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif public int f() http://www.agoit.com/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return 2;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockEnd.gif}
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