Q:

Information separating from mysql

I'm making program for teachers with Java and mysql , so I've many tables in mysql such as students table which contains student name and number and ID .. etc , also another table that called groups , It contains group name , place and students .. etc.
So , the problem is , in Groups table I'll add IDs of students in one row just like the image bellow beside the name of group , how can I take this IDs from mysql in this form and separate them automatically in program by java to search in the students table about the information of them .
image : http://i.stack.imgur.com/NFQ6t.jpg
  try {
    Class.forName("java.sql.Driver");
    Connection con = (Connection)   DriverManager.getConnection("jdbc:mysql://localhost:3306/teacherassistant?allowMultiQueries=true","root","1234");
    Statement st = (Statement) con.createStatement();
    String query = "select * from Groups;";
    ResultSet rs = st.executeQuery(query);

    while(rs.next()){
    String name = rs.getString("Name");
    String StudentIDs= rs.getString("Students");
    String Center = rs.getString("Center");

    }

    } catch (Exception e) {
        JOptionPane.showMessageDialog(this,"Error");
    }

A:

Don't do that.
The relationship between groups and students is clearly a many-to-many relationship. Instead make a new table that contains this relationship. Something like;
STUDENT_GROUP_REL
------------------
(student_id, group_id)

There is a related question and a very good answer about m:n relations here

