Everytime I run my database and put in the appropriate values, it will always result in null, what seems to be the problem?

private void jAddActionPerformed(java.awt.event.ActionEvent evt) {

String code = jCode.getText();
String registrationNumberText = jRegistrationNumber.getText();
String barcodeText = jBarcode.getText();
String maincharName = jMaincharName.getText();
String title = jTitle.getText();
String version = jVersion.getText();
String size = jSize.getSelectedItem().toString();

if (code.isEmpty() || registrationNumberText.isEmpty() || barcodeText.isEmpty()) {
    // Handle the case where any of the required fields are empty
    System.out.println("Please fill in all the required fields.");
    return; // Exit the method to prevent further execution
}

int registrationNumber;
int barcode;

try {
    registrationNumber = Integer.parseInt(registrationNumberText);
    barcode = Integer.parseInt(barcodeText);
} catch (NumberFormatException e) {
    // Handle the case where the input strings cannot be parsed as integers
    System.out.println("Invalid input for registration number or barcode.");
    e.printStackTrace();
    return; // Exit the method to prevent further execution
}

Collection collect = new Collection(code, registrationNumber, barcode, maincharName, title, version, size);
CollectionRepository cr = new CollectionRepository();
cr.insertProduct(collect);
jCode.setText("");
jRegistrationNumber.setText("");
jBarcode.setText("");
jMaincharName.setText("");
jTitle.setText("");
jVersion.setText("");
jSize.setSelectedItem("");

view();

}

private void jAddActionPerformed(java.awt.event.ActionEvent evt) {                                     
                                   
    String code = jCode.getText();
    String registrationNumberText = jRegistrationNumber.getText();
    String barcodeText = jBarcode.getText();
    String maincharName = jMaincharName.getText();
    String title = jTitle.getText();
    String version = jVersion.getText();
    String size = jSize.getSelectedItem().toString();

    if (code.isEmpty() || registrationNumberText.isEmpty() || barcodeText.isEmpty()) {
        // Handle the case where any of the required fields are empty
        System.out.println("Please fill in all the required fields.");
        return; // Exit the method to prevent further execution
    }

    int registrationNumber;
    int barcode;

    try {
        registrationNumber = Integer.parseInt(registrationNumberText);
        barcode = Integer.parseInt(barcodeText);
    } catch (NumberFormatException e) {
        // Handle the case where the input strings cannot be parsed as integers
        System.out.println("Invalid input for registration number or barcode.");
        e.printStackTrace();
        return; // Exit the method to prevent further execution
    }

    Collection collect = new Collection(code, registrationNumber, barcode, maincharName, title, version, size);
    CollectionRepository cr = new CollectionRepository();
    cr.insertProduct(collect);
    jCode.setText("");
    jRegistrationNumber.setText("");
    jBarcode.setText("");
    jMaincharName.setText("");
    jTitle.setText("");
    jVersion.setText("");
    jSize.setSelectedItem("");  
        
    view();

    }