Multiple depended Combo-boxes in Swing

Solution for Multiple depended Combo-boxes in Swing
is Given Below:

My code on student registration requires, select course depending upon the selected stream which is dependent upon the discipline.
Ex: Discipline PostGraduation enables multiple streams and from them, if we select ‘law’ is must show law-related courses in the course combo box.
I have achieved stream Combobox dependent upon discipline Combobox. Any optimal approach for these all combo boxes.

private void Combo_desciplineActionPerformed(java.awt.event.ActionEvent evt) {                                                 
         // TODO add your handling code here:
         if(Combo_descipline.getSelectedItem().equals("Certificate")){
             Combo_stream.removeAllItems();
             Combo_stream.addItem("Agriculture");
             Combo_stream.addItem("Fashion Design and Technology");
             Combo_stream.addItem("Film Technology");
             Combo_stream.setSelectedItem(null);
         }
         else if(Combo_descipline.getSelectedItem().equals("Diploma")){
             Combo_stream.removeAllItems();
             Combo_stream.addItem("Agriculture");
             Combo_stream.addItem("Fashion Design and Technology");
             Combo_stream.addItem("Film Technology");
             Combo_stream.addItem("Healthcare and Allied Sciences");
             Combo_stream.addItem("Management");
             Combo_stream.addItem("Media and Mass Communication");
             Combo_stream.addItem("Pharmacy");
             Combo_stream.addItem("Polytechnic");
             Combo_stream.addItem("Yoga and Vedic Science");  
             Combo_stream.setSelectedItem(null);
         }
         else if(Combo_descipline.getSelectedItem().equals("Integreted")){
             Combo_stream.removeAllItems();
             Combo_stream.addItem("Agriculture");
             Combo_stream.addItem("Arts");
             Combo_stream.addItem("Commerce");
             Combo_stream.addItem("Computer Science and IT");
             Combo_stream.addItem("Education");
             Combo_stream.addItem("Engineering and Technology");
             Combo_stream.addItem("Fashion Design and Technology");
             Combo_stream.addItem("Law");
             Combo_stream.addItem("Management");
             Combo_stream.addItem("Science");    
             Combo_stream.setSelectedItem(null);
         }
         else if(Combo_descipline.getSelectedItem().equals("Lateral Entry")){
             Combo_stream.removeAllItems();
             Combo_stream.addItem("Engineering and Technology");
             Combo_stream.addItem("Fashion Design and Technology");
             Combo_stream.addItem("Polytechnic");     
             Combo_stream.setSelectedItem(null);
         }
         else if(Combo_descipline.getSelectedItem().equals("PG")){
             Combo_stream.removeAllItems();
             Combo_stream.addItem("Agriculture");
             Combo_stream.addItem("Arts");
             Combo_stream.addItem("Commerce");
             Combo_stream.addItem("Computer Science and IT");
             Combo_stream.addItem("Education");
             Combo_stream.addItem("Engineering and Technology");
             Combo_stream.addItem("Fashion Design and Technology");
             Combo_stream.addItem("Film Technology");
             Combo_stream.addItem("Healthcare and Allied Sciences");
             Combo_stream.addItem("Home Science");
             Combo_stream.addItem("Law");
             Combo_stream.addItem("Management");
             Combo_stream.addItem("Media and Mass Communication");
             Combo_stream.addItem("Pharmacy");
             Combo_stream.addItem("Physiotherapy");
             Combo_stream.addItem("Science");             
             Combo_stream.addItem("Yoga and Vedic Science");
             Combo_stream.setSelectedItem(null);
         }
         else if(Combo_descipline.getSelectedItem().equals("PG Diploma")){
             Combo_stream.removeAllItems();
             Combo_stream.addItem("Agriculture");
             Combo_stream.addItem("Arts");             
             Combo_stream.addItem("Computer Science and IT");
             Combo_stream.addItem("Fashion Design and Technology");
             Combo_stream.addItem("Film Technology");
             Combo_stream.addItem("Healthcare and Allied Sciences");
             Combo_stream.addItem("Home Science");
             Combo_stream.addItem("Law");
             Combo_stream.addItem("Management");
             Combo_stream.addItem("Media and Mass Communication");
             Combo_stream.addItem("Pharmacy");
             Combo_stream.addItem("Science");             
             Combo_stream.addItem("Yoga and Vedic Science");
             Combo_stream.setSelectedItem(null);
         }
          else if(Combo_descipline.getSelectedItem().equals("Phd/MPhil")){
             Combo_stream.removeAllItems();
             Combo_stream.addItem("Agriculture");
             Combo_stream.addItem("Arts");  
             Combo_stream.addItem("Commerce");
             Combo_stream.addItem("Computer Science and IT");
             Combo_stream.addItem("Education");             
             Combo_stream.addItem("Engineering and Technology");
             Combo_stream.addItem("Fashion Design and Technology");
             Combo_stream.addItem("Film Technology");
             Combo_stream.addItem("Healthcare and Allied Sciences");
             Combo_stream.addItem("Home Science");
             Combo_stream.addItem("Law");
             Combo_stream.addItem("Management");
             Combo_stream.addItem("Media and Mass Communication");
             Combo_stream.addItem("Pharmacy");
             Combo_stream.addItem("Science");             
             Combo_stream.addItem("Yoga and Vedic Science");
             Combo_stream.setSelectedItem(null);
         }
         else if(Combo_descipline.getSelectedItem().equals("UG")){
             Combo_stream.removeAllItems();
             Combo_stream.addItem("Agriculture");
             Combo_stream.addItem("Arts");
             Combo_stream.addItem("Commerce");
             Combo_stream.addItem("Computer Science and IT");
             Combo_stream.addItem("Education");
             Combo_stream.addItem("Engineering and Technology");
             Combo_stream.addItem("Fashion Design and Technology");
             Combo_stream.addItem("Film Technology");
             Combo_stream.addItem("Healthcare and Allied Sciences");
             Combo_stream.addItem("Home Science");
             Combo_stream.addItem("Law");
             Combo_stream.addItem("Management");
             Combo_stream.addItem("Media and Mass Communication");
             Combo_stream.addItem("Pharmacy");
             Combo_stream.addItem("Physiotherapy");
             Combo_stream.addItem("Science");             
             Combo_stream.addItem("Yoga and Vedic Science");             
             Combo_stream.setSelectedItem(null);
         }
         
    } 

It should look like this:

sample