// Add the value when the button is clicked
    // calls the storeMemo() function in the memopad class and passes the text from the text field into the storememo function
    private void addButtonActionPerformed(java.awt.event.ActionEvent evt) {                                          
        memopad.storeMemo(memoTF.getText());
        memoTF.setText(" ");
        jTextArea1.setEditable(false);
    }

    // do a loop
    // the error you're getting is due to only 1 entry being in the arraylist, whereas we are looping 20 times, ignore it 
    // set jTextArea1 to show the result returned from showMemos
    private void updateButtonActionPerformed(java.awt.event.ActionEvent evt) {                                             
        int i;
        
        for(i=0; i<20; i++){
            if(i<1){
                jTextArea1.setText(memopad.showMemos(i) + newline);
            }else{
                jTextArea1.append(memopad.showMemos(i) + newline);
            }
        }   
    }  

    public String showMemos(int i)
    {
        return memos.get(i);
    }