Question

In the following code, if jcbValue evaluates to Find, I have it set to print the contents of the hashmap. It is returning NULL. I am assuming this means that by that point the contents of the hashmap have been emptied.

My questions are as follows;
1) What am I doing wrong?
2) How do I fix it?

Thanks,
CJ

   public class ButtonListener implements ActionListener {
   public void actionPerformed(ActionEvent e) {

        HashMap<String, ArrayList> map = new HashMap<String, ArrayList>();

        String jcbValue = (String) jcbIDF.getSelectedItem();
        if (jcbValue == "Insert") {

            String Id = jtfId.getText();
            ArrayList<String> ValueList = new ArrayList<String>();
            String Name = jtfName.getText();
            String GPA = jtfGPA.getText();
            ValueList.add(Name);
            ValueList.add(GPA);
            map.put(Id, ValueList);
            System.out.println(map);

            JOptionPane.showMessageDialog(null, "Record Inserted",
                    "Result", JOptionPane.INFORMATION_MESSAGE);
            // jtfId.setText("");
            // jtfName.setText("");
            // jtfGPA.setText("");
        } else if (jcbValue == "Delete") {
            System.out.println(map);
            JOptionPane.showMessageDialog(null,
                    "Delete Selected; But Not Implemented", "Result",
                    JOptionPane.INFORMATION_MESSAGE);
        } else if (jcbValue == "Find") {
            System.out.println(map);
            JOptionPane.showMessageDialog(null,
    "Find Selected; But not Implemented", "Result",
                    JOptionPane.INFORMATION_MESSAGE);
        }
    }// Terminates actionPerformed Class
    }// Terminates ButtonListenerClass        

Answer 1

You’re creating a new map every time you hit actionPerformed, so nothing will ever persist across calls to it.

The map needs to exist as something other than a local variable in the action handler.

(And as AVD says, your comparison is incorrect.)