????????????Щ??????????t?????

????1??????????????ж??幹????????????????????????????????ι???????


public ClassName {}


????2??this ?? super ??????

????3???????????????Object??????Object????????ι???????

????4??????????????????????????????????????????ι????????????super()??

??????????????????


class Employee extends Object {

 public Employee(int id) {
 }
}

class Teacher extends Employee {
 
 public Teacher() {
 }
}
 


??????????????????????


Implicit super constructor Employee() is undefined. Must explicitly invoke another constructor


?????????????????????????????????????????????????????ι?????????????????????????????????????????????????????????????????????super()?????? ????????в??????????ι???????????????????ι?????δ???????

????????????


class Employee {

 public Employee(int id) {
 }
}

class Teacher extends Employee {
 
 public Teacher() {
  super(10);
 }
}
 


???????????????????????????????????????????????????????????????????super()??????

??????????????????η???

????????????public??protected??default??private???Σ????????private?????????????????????????