Why the getMethod for List<String> is not printing out the values in another Method?

[tangara]

I have been dealing with this problem for the longest time and I really hope someone can tell me what's happening and how to make the getMethod for List<String> returns the values.

public void insertTutor_Subject(int tutor_id, List<String> subjNames) throws MyDataException {
		
		Tutor m = new Tutor();
		System.out.println(tutor_id); //this will return the generated_id
		System.out.println(m.getSubjects());//not able to print out
try {
			//openConnection();		
			PreparedStatement ps3 = connection.prepareStatement("INSERT INTO project.tutor_subject(tutor_id, subjectName) VALUES (?, ?);");
			ps3.setInt(1, tutor_id);
			//System.out.println(m.getTutor_id()); //m.getTutor_id() will give you 0
			ps3.setObject(2, m.getSubjects());
			System.out.println(m.getSubjects());
			ps3.addBatch();
			ps3.setInt(1, tutor_id);
			ps3.setObject(2, m.getSubjects());
			ps3.addBatch();

At my controller :

String[] subj = request.getParameterValues("subject");
			List<String>subjs = new ArrayList<String>(Arrays.asList(subj));
		    m4.setSubjects(subjs); 
		    System.out.println(m4.getSubjects());	// able to see the values

My first question is m4.getSubjects at the controller is able to return the value so why is it not showing up at the insertTutor_Subject method?

My 2nd question is do I still need to OpenConnection(static method for JDBC Connection) in order for the insertion to work?

My last question is if the above - using Batch to insert the List<String> ? Is there anything wrong with this method ?

Thanks

[Norm]

Can you make and post a small complete program that compiles, executes and shows the problem?

Please wrap all posted code in code tags to preserve formatting.

[Arjay]

The reason is that in the following method you are declaring a new Tutor object, but aren't populating it.

public void insertTutor_Subject(int tutor_id, List<String> subjNames) throws MyDataException {
		
		Tutor m = new Tutor();
		System.out.println(tutor_id); //this will return the generated_id
		System.out.println(m.getSubjects());//not able to print out -- YES, because it's empty

The following works because you call m4.setSubjects (presumably m4 is an instance of the Tutor object).

String[] subj = request.getParameterValues("subject");
			List<String>subjs = new ArrayList<String>(Arrays.asList(subj));
		    m4.setSubjects(subjs); // SETTING the VALUES
		    System.out.println(m4.getSubjects());	// able to see the values

Do you have to call setSubjects() first?

public void insertTutor_Subject(int tutor_id, List<String> subjNames) throws MyDataException {
		
		Tutor m = new Tutor();
		System.out.println(tutor_id);
                m.setSubjects(subjNames);
		System.out.println(m.getSubjects());