Read and Modify PDF Form Field Values

• Jul 13, 2026
• 4 minutes to read

The PDF Document API allows you to read and modify values stored in AcroForm fields. Locate a field in the document before you access its value (see Access and Find PDF Form Fields).

Read and Modify a Text Field

Cast the field to TextBoxField to access its value.

The following code snippet reads and updates the value of a text field:

// Find the text field by its name.
FormField field = pdfDocument.getFields().findByName("FirstName");

if(field instanceof TextBoxField textBoxField) {
    // Read the current value.
    String value = textBoxField.getValue();

    // Update the field value.
    textBoxField.setValue("Alice");
}

Read and Modify a Check Box

Use getChecked() and setChecked(boolean value) methods to read or modify the check box state.

The following code snippet selects a check box:

// Find the check box field.
FormField field = pdfDocument.getFields().findByName("AgreeToTerms");

if(field instanceof CheckBoxField checkBoxField) {
    // Select the check box.
    checkBoxField.setChecked(true);
}

Read and Modify a Combo Box

A combo box stores one selected value.

The following code snippet updates the selected value:

// Find the combo box field.
FormField field = pdfDocument.getFields().findByName("Country");

if(field instanceof ComboBoxField comboBoxField) {
    // Change the selected value.
    comboBoxField.setValue("Canada");

    // Read the current value.
    String value = comboBoxField.getValue();
}

Tip

Use the ComboBoxField.getItems() method to access combo box items (ChoiceFieldItem objects).

Read and Modify a Radio Button Group

A radio button group stores the value of the selected option.

The following code snippet selects a radio button:

// Find the radio button group.
FormField field = pdfDocument.getFields().findByName("Gender");

if(field instanceof RadioGroupField radioGroupField) {
    // Select an option.
    radioGroupField.setValue("Female");

    // Read the selected option.
    String value = radioGroupField.getValue();
}

Read and Modify a List Box

Use list box selection methods to read or modify selected items.

The following code snippet selects an item in a list box:

// Find the list box field.
FormField field = pdfDocument.getFields().findByName("Country");

if(field instanceof ListBoxField listBoxField) {
    // Select an item.
    // listBoxField.selectValue("Germany");

    // Select items.
    listBoxField.setSelectedValues(Arrays.asList(
            "USA",
            "Canada"
    ));

    // Get selected values.
    for (String value : listBoxField.getSelectedValues()) {
        System.out.println(value);
    }
}

To select or clear a specific item by index, call the setSelected(int index, boolean value) method.

// Select the first item.
listBoxField.setSelected(0, true);

// Clear the second item.
listBoxField.setSelected(1, false);

If multiple item selection is enabled, use the setSelectedValues() method to select specific items:

listBoxField.setSelectedValues(List.of("USA", "Canada"));

Tip

Use the ListBoxField.getItems() method to access list box items (ChoiceFieldItem objects).

Read Signature Information

The following code snippet reads the signer information from a signed signature field:

// Find the signature field.
FormField field = pdfDocument.getFields().findByName("Signature");

if(field instanceof SignatureField signatureField) {
    if(signatureField.getIsSigned()) {
        // Read signature information.
        String signer = signatureField.getSignerName();
        String reason = signatureField.getReason();
        String contact = signatureField.getContactInfo();
        var signingTime = signatureField.getSigningTime();
    }
}

Make a Form Field Read-Only

To prevent users from modifying a field, call the FormField.setReadOnly() method and pass true.

The following code snippet makes a field read-only:

// Find the field.
FormField field = pdfDocument.getFields().findByName("FirstName");

// Prevent users from editing the field.
field.setReadOnly(true);

Mark a Form Field as Required

Call the FormField.setRequired(boolean) method to mark a form field as required.

The following code snippet adds a mandatory Email field to the first page in a PDF document:

Page page = pdfDocument.getPages().getFirst();

// Create a mandatory text field.
TextBoxField emailField = new TextBoxField("Email");
emailField.setRequired(true);
pdfDocument.getFields().add(emailField);

// Bind the field to a widget and place it on the page.
RectangleF bounds = new RectangleF(120, 720, 220, 20);
TextBoxWidgetAnnotation widget = new TextBoxWidgetAnnotation(emailField, bounds);
widget.setFontSize(12);

page.getAnnotations().add(widget);

Note

The required flag marks a field as mandatory. PDF viewers and processors determine whether and how to highlight required fields and enforce this requirement during form submission.