Stack added items on JList
<p>I'm trying to transfer the selected items from a source JList and destination JList on button click. So what I did is this. </p>

<pre><code>private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        int index = AddSubjectsToCurriculum.getSelectedIndex();
        String selectedItemOnSourceList = AddSubjectsToCurriculum.getSelectedValue().toString(); 
        int x = 0;

        if(index &gt;= 0) // --if atleast 1 is selected
        {
            DefaultListModel dlm = new DefaultListModel(); //--declare a placeholder for items you will add
                dlm.add(x++,selectedItemOnSourceList); // --add the selected item to dlm 
                CurriculumSubjects.setModel(dlm); //--at this point item has been added already
            ((DefaultListModel)AddSubjectsToCurriculum.getModel()).remove(index); // --remove what was selected from source list
        }//end of if
    }
</code></pre>

<p>But everytime I click the button, it only adds the selected item from source list but never populates or updates the destination list with new elements added. How do I fix this? I need to setModel() everytime button is clicked but I need to be able to move forward to the next index on next button click.</p>

<p>Only adds one and shows one element for every <code>&gt;</code> button click</p>

<p><a href="https://i.stack.imgur.com/n9zAH.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/n9zAH.jpg" alt="enter image description here"></a></p>

<p>I'd appreciate any help. Thanks. </p>