Course

//Course.java
public class Course {
  private String courseName;
  private String[] students = new String[4];
  private int numberOfStudents;

  /**
   *
   * @param courseName is a string passed on when an object of Course class is inititated
   */
  public Course(String courseName) {
    this.courseName = courseName;
  }

  /**
   * This method is used to add students in our string array students.
   * It automatically doubles it's size if the array is running out of space.
   * @param student is only parameter to addStudent method
   */
  public void addStudent(String student) {
    if (students.length == numberOfStudents) {
      String[] temp = new String[numberOfStudents * 2];
      for (int i = 0; i < students.length; i++) {
        temp[i] = students[i];
      }
      students = temp;
    }
    students[numberOfStudents] = student;
    numberOfStudents++;
  }

  /**
   * This method is used to get all students enrolled in current course.
   * @return String[] This returns array of students.
   */
  public String[] getStudents() {
    return students;
  }

  /**
   * This method is used to get number of students enrolled in our course.
   * @return int This retuns int value of students in our course.
   */
  public int getNumberOfStudents() {
    return numberOfStudents;
  }

  /**
   * This method is used to get name of the course.
   * @return String This returns course name String value.
   */
  public String getCourseName() {
    return courseName;
  }

  /**
   * This method is used to remove student from our course.
   * @param student is the only parameter required to know which student to be removed.
   */
  public void dropStudent(String student) {
    String[] temp = new String[numberOfStudents];
    int count = 0;
    for (int i = 0; i < students.length; i++) {
      if (students[i] == null || students[i].equals(student)) {
        continue;
      }
      temp[count] = students[i];
      count++;
    }
    students = temp;
    numberOfStudents--;
  }
}
//TestCourse.java
public class TestCourse {
  public static void main(String[] args) {
    Course c1 = new Course("MBBS");
    c1.addStudent("Rick Astley");
    c1.addStudent("Dick Dale");
    c1.addStudent("Candice");
    c1.dropStudent("Rick Astley");
    String[] students = c1.getStudents();
    for (String student : students) {
      System.out.println(student);
    }
  }
}