重写 overwrite或者override: 相同的方法名称, 参数列表和返回类型

重载overload: 方法有相同的名字, 但是参数不同 (参数个数不同, 参数类型不同, 其中一个不同即可),

重写的方法的访问权限不能比父类的方法权限更严格.

比如父类的方法是protected, 那么子类覆写的方法的权限是protected或者public

overwrite:

class Person {

private String name;

private int age;

public void setName(String name){this.name=name;}

public void setAge(int age) {this.age=age;}

public String getName(){return name;}

public int getAge(){return age;}

public String getInfo() {

return "Name: "+ name + "\n" +"age: "+ age;

}

}

class Student extends Person {

private String school;

public String getSchool() {return school;}

public void setSchool(String school)

{this.school =school;}

public String getInfo() {

return "Name: "+ getName() + "\nage: "+ getAge()

+ "\nschool: "+ school;

}

}

public class TestOverWrite {

public static void main(String arg[]){

Student student = new Student();

Person person = new Person();

person.setName("none");

person.setAge(1000);

student.setName("John");

student.setAge(18);

student.setSchool("SCH");

System.out.println(person.getInfo());

System.out.println(student.getInfo());

}

}

overload:

public class Test {

void max(int a , int b) {

System.out.println( a > b ? a : b );

}

void max(short a , short b) {

System.out.println("short");

System.out.println( a > b ? a : b );

}

void max(float a, float b) {

System.out.println( a > b ? a : b );

}

public static void main(String[] args) {

Test t = new Test();

t.max(3, 4);

short a = 3;

short b = 4;

t.max(a, b);

}

}