Retrieve Data From Database By Joining Tables

I am trying to retrieve data from my database by joining my tables. So far i have managed to join my four tables in my database and retrieve all the information in that table. Now what i want to do is create a prepared statement in java that allows me to retreive certain data. Here is my joining query.

SELECT student.idNumber,student.names, student.surname,
course.description,
coursemarks.mark,
class.form,class.id
FROM `student`
LEFT JOIN `coursemarks` on student.idNumber = coursemarks.studentid
LEFT JOIN `course` on course.courseid = coursemarks.courseid
LEFT JOIN `class`on student.idNumber = class.studentID;

What I want is to select all the data depending on the class passed and the form passed, e.g a person might decide to select a certain form only or a certain form and class