List to be visible only when entering any string into textfield

package tests;

import java.awt.event.KeyEvent;

import java.util.ArrayList;

import javax.swing.DefaultListModel;

import javax.swing.JPopupMenu;

public class PopUpMenu1 extends javax.swing.JFrame {

DefaultListModel lsm = new DefaultListModel();
JPopupMenu jpm = new JPopupMenu();
ArrayList<String> arls;

/** Creates new form PopUpMenu1 */
public PopUpMenu1() {


    jList2 = new javax.swing.JList();

    jList2.setModel(lsm);

    jList2.setSelectedIndex(1);

//jScrollPane1.setViewportView(jList1);

    arls = new ArrayList();

    for (int i = 0; i < 10; i++) {

        arls.add(i + "abcd" + i);

        lsm.addElement(i + "abcd" + i);

    }

    jpm.add(jList2);

    initComponents();

}

@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">//GEN-BEGIN:initComponents
private void initComponents() {

    jTextField1 = new javax.swing.JTextField();
    jScrollPane1 = new javax.swing.JScrollPane();
    jList1 = new javax.swing.JList();
    jButton1 = new javax.swing.JButton();
    jCheckBox1 = new javax.swing.JCheckBox();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jTextField1.setComponentPopupMenu(jpm);
    jTextField1.addCaretListener(new javax.swing.event.CaretListener() {

        public void caretUpdate(javax.swing.event.CaretEvent evt) {
            jTextField1CaretUpdate(evt);
        }
    });
    jTextField1.addFocusListener(new java.awt.event.FocusAdapter() {

        public void focusGained(java.awt.event.FocusEvent evt) {
            jTextField1FocusGained(evt);
        }
    });
    jTextField1.addKeyListener(new java.awt.event.KeyAdapter() {

        public void keyReleased(java.awt.event.KeyEvent evt) {
            jTextField1KeyReleased(evt);
        }
    });

    jList1.setModel(lsm);
    jScrollPane1.setViewportView(jList1);

    jButton1.setText("jButton1");

    jCheckBox1.setText("jCheckBox1");

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING).addGroup(layout.createSequentialGroup().addGap(35, 35, 35).addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING).addComponent(jCheckBox1, javax.swing.GroupLayout.DEFAULT_SIZE, 381, Short.MAX_VALUE).addGroup(layout.createSequentialGroup().addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false).addComponent(jScrollPane1).addComponent(jTextField1, javax.swing.GroupLayout.DEFAULT_SIZE, 122, Short.MAX_VALUE)).addGap(40, 40, 40).addComponent(jButton1))).addContainerGap()));
    layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING).addGroup(layout.createSequentialGroup().addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING).addGroup(layout.createSequentialGroup().addGap(25, 25, 25).addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING).addGroup(layout.createSequentialGroup().addGap(35, 35, 35).addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE).addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED).addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)).addGroup(layout.createSequentialGroup().addGap(52, 52, 52).addComponent(jButton1)))).addGroup(layout.createSequentialGroup().addContainerGap().addComponent(jCheckBox1))).addContainerGap(81, Short.MAX_VALUE)));

    pack();
}// </editor-fold>//GEN-END:initComponents

private void jTextField1FocusGained(java.awt.event.FocusEvent evt) {//GEN-FIRST:event_jTextField1FocusGained
    // TODO add your handling code here:
    jpm.show(this, jTextField1.getX() + 50, jTextField1.getY() + 50);
    jTextField1.requestFocus();
//jpm.setVisible(false);
//jTextField1.setComponentPopupMenu(jpm);
}//GEN-LAST:event_jTextField1FocusGained

private void jTextField1KeyReleased(java.awt.event.KeyEvent evt) {//GEN-FIRST:event_jTextField1KeyReleased
    // TODO add your handling code here:
    if (evt.getKeyCode() == KeyEvent.VK_DOWN) {
        // Do stuff.
        if (jList2.getSelectedIndex() == lsm.getSize() - 1) {
            jList2.setSelectedIndex(0);
        } else {
            jList2.setSelectedIndex(jList2.getSelectedIndex() + 1);
        }
    }
    if (evt.getKeyCode() == KeyEvent.VK_UP) {
        if (jList2.getSelectedIndex() == 0) {
            jList2.setSelectedIndex(lsm.getSize() - 1);
        } else {
            jList2.setSelectedIndex(jList2.getSelectedIndex() - 1);
        }
    }
    if (evt.getKeyCode() == KeyEvent.VK_ENTER) {
        jTextField1.setText((String) jList2.getSelectedValue());
    }


}//GEN-LAST:event_jTextField1KeyReleased

private void jTextField1CaretUpdate(javax.swing.event.CaretEvent evt) {//GEN-FIRST:event_jTextField1CaretUpdate
    // TODO add your handling code here:
    String starts = jTextField1.getText();
    lsm.removeAllElements();
    for (String elem : arls) {
        if (elem.startsWith(starts)) {
            lsm.addElement(elem);
        }
    }
    jTextField1.requestFocus();
}//GEN-LAST:event_jTextField1CaretUpdate

/**
 * @param args the command line arguments
 */
public static void main(String args[]) {
    java.awt.EventQueue.invokeLater(new Runnable() {

        public void run() {
            new PopUpMenu1().setVisible(true);
        }
    });
}

// Variables declaration - do not modify//GEN-BEGIN:variables
private javax.swing.JButton jButton1;
private javax.swing.JCheckBox jCheckBox1;
private javax.swing.JList jList1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextField jTextField1;
// End of variables declaration//GEN-END:variables
private javax.swing.JList jList2;

}