content: package gr.aueb.cf.ch12;
  
  /**
   * Data class.
   * POJO (Plain Old Java Object)
   * Java Bean.
   */
  public class Student {
      private static int studentsCount = 0;
  
      private int id;
      private String firstname;
      private String lastname;
  
      static {
          studentsCount = 0;
      }
  
      // Default Constructor
      public Student() {
          studentsCount++;
      }
  
      // Overloaded Constructor
      public Student(int id, String firstname, String lastname) {
          this.id = id;
          this.firstname = firstname;
          this.lastname = lastname;
          studentsCount++;
      }
  
      public static int getStudentsCount() {
          return studentsCount;
      }
  
      public int getId() {
          return id;
      }
  
      public void setId(int id) {
          this.id = id;
      }
  
      public String getFirstname() {
          return firstname;
      }
  
      public void setFirstname(String firstname) {
          this.firstname = firstname;
      }
  
      public String getLastname() {
          return lastname;
      }
  
      public void setLastname(String lastname) {
          this.lastname = lastname;
      }
  }
  