}
=========运行结果========
Exception in thread "main" java.lang.NullPointerException
at swap.<init>(swap.java:8)
at swap.main(swap.java:4)
==========解答:
this.name作为全局变量默认为NULL,NULL对象.ToStrign();就会出现错误!
全局变量和局部变量重复之this.name.toString());Exception in thread "main" java.lang.NullPointerException
原文:http://blog.csdn.net/yangdong3129/article/details/20215107