Getting null values from checkboxes - spring-mvc

Question

I am working on a simple Spring MVC project. I am having trouble getting values from checkboxes. What I mean is when a user checks 2 boxes out of 3, all 3 are binded to a list with non-checked values as null. That's wrong. I just want values that are checked. Those that didn't get checked should not come to list at all.
This is a snippet of my code:
POJO:
public class Student{
private List<StudentCourses> sc;
//getters and setters
}
public class StudentCourses{
private int courseID;
private String courseName;
private Character grade;
private String semesterID;
//getters and setters
}
This is what I send from my controller:
#RequestMapping(value = "/selectclasses", method = RequestMethod.POST)
public String selectClasses(Model m) {
Student s = new Student();
List<StudentCourses> coursesList = new ArrayList<StudentCourses>();
coursesList.add(new StudentCourses("Eng 101", '-', "SP 16"));
coursesList.add(new StudentCourses("Math 140", '-', "SP 16"));
coursesList.add(new StudentCourses("CS 442", '-', "SP 16"));
m.addAttribute("coursesList", coursesList);
m.addAttribute("student", s);
return "selectclasses";
}
This is what I have in my selectclasses.jsp:
<form:form modelAttribute="student" method="post" action="/success">
<table>
<c:forEach items="${coursesList}" var="r" begin="0" varStatus="status">
<form:checkbox path="sc[${status.index }].courseName" value="${r.courseName}" label="${r.courseName}" />
</c:forEach>
</table>
<input type="submit" id="submit" name="submit" value="Submit" />
</form:form>
I don't know why null is passed to the "sc.courseName" when it's not checked. What am I doing wrong? Or is there a work around it?
Please help
Thanks.

Answer 1

simply writer
<input type="checkbox" value="${r.courseName}" id="id"name="name"/>
in controller class get the values using
String []values=request.getParameterValues(pass the id);
simple you get the selected values

Answer 2

I found the Solution!
I found two ways to solve it. This is the solution using Spring tags:
<form:checkboxes path="sc" items="${coursesList}" itemValue="courseName" itemLabel="courseName" />
In the above code, itemValue and itemLabel is the main thing! itemValue and itemLabel simply refer to bean properties of an object inside items attribute (items="${coursesList}"). In a nutshell, if you need to use a List of your Custom Beans as the items attribute you need to use also the itemValue and itemLabel attributes. This bold part of paragraph is taken from: https://stackoverflow.com/a/15529281/4828463 by #Carlos Gavidia
And now the solution using JSTL core tags:
<c:forEach items="${coursesList}" var="courses">
<tr>
<td><form:checkbox path="sc" value="${courses.courseName}" label="${courses.courseName}"/></td>
</tr>
</c:forEach>
Again the value and label attributes are important.