摘要：
class People { String name; public People() { System.out.print(1); } public People(String name) { System.out.print(2); this.name = name; }}class Child 阅读全文
摘要：
Dervied tell name: nullDervied print name: nullDervied tell name: derviedDervied print name: dervied 阅读全文