下面程序有两个错误，但刚学java，不太了解有参和无参构造方法，哪位大神能帮忙指点一下

class Student{
     private String name;
     private int grade;
 
  public String getName(){
      return name;
  }
  public void setName(String name1){
      name=name1;
  }
  public int getGrade(){
      return grade;
  }
  public void setGrade(int grade1){
      if(grade1<0){
         System.out.println("成绩错误");
      }else{
          grade=grade1;
      }
   }
  public Student(String name,int grade){
        this.name=name;
        this.grade=grade;
  }   
public class xinxin {
    public static void main(String[] args) {
       Student stu1=new Student();
       stu1.setName("张三");
       stu1.setGrade(100);
       Student stu2=new Student("李四",59);
      
    }
}
 }