求助！谁可以解释一下呢？
如下代码:
public class StudentBuffer{ static Vector studentBuffer = new Vector(); ... public void addStudent(Student theStudent){ studentBuffer.addElement(theStudent); } public Student type1GetStudent(int id){ Student tmpStudent; for(i=0;i<student.size();i++){ tmpStudent = (Student)studentBuffer.elementAt(i); if(tmpStudent.id == id){ return tmpStudent; } } return null; } public Student type2GetStudent(int id){ Student tmpStudent; for(i=0;i<student.size();i++){ tmpStudent = (Student)studentBuffer.elementAt(i); if(tmpStudent.id == id){ Student retStudent = tmpStudent; return retStudent; } } return null; }}