java 语言的“this”的三种用法

java 语言的“this”的三种用法
这是代码,我们老师叫我们添加代码,使用this的三种用法,请添加this并注释.
package exp3.entities;
public class Student {
private String name;
private String speciality;
private int id;
private float credit;
public Student(String name,int id,String speciality,float credit){
this.name=name;
this.id=id;
this.speciality=speciality;
this.credit=credit;
}
static int creditForGraduation=6;
public int getCreditForGraduation(){
return creditForGraduation;
}
public String getName(){
return name;
}
public int getId(){
return id;
}
public String getSpeciality(){
return speciality;
}
public float getCredit(){
return credit;
}
public void judgeCredit(String theClass){
if(credit==9)
theClass="优";
else if(credit>=6&&credit