Find record by one of the composite primary keys

I have composite primary key in one of my tables in Java web app using Hibernate framework:

For example:

@Embeddable
public class Student implements Serializable {    
    @Column(name = "student_id")
    private String studentId;

    @Column(name = "course_code")
    private String courseCode;
}

I can filter records by both fields. However, I want to search for a record with studentId only. How would it be possible in Hibernate?