Filling multiple fields in PDF form using PDFBOX and Lock editing of pdf document after filling - pdfbox

Question

I am new to PDF BOX, need to fill the information in PDF Form, which has sections and field names:
PDF form contains information of
NAME
and box to fill the information
Address
and box to fill the information
City
box to fill the information.
if i have the Name, Address and city information how to fill that into the pdf form using pdf box.
Have used the example from PDFbox, acroForm only fills sample fields how to get this filled with particular information at particular field.
once after filling it how to make it locked.
String formTemplate = "C:/FillFormField.pdf";
PDDocument pdfDocument = PDDocument.load(new File(formTemplate))
// get the document catalog
PDAcroForm acroForm = pdfDocument.getDocumentCatalog().getAcroForm();
// as there might not be an AcroForm entry a null check is necessary
if (acroForm != null)
{
// Retrieve an individual field and set its value.
PDTextField field = (PDTextField) acroForm.getField( "sampleField" );
field.setValue("Text Entry");
// If a field is nested within the form tree a fully qualified name
// might be provided to access the field.
field = (PDTextField) acroForm.getField( "fieldsContainer.nestedSampleField" );
field.setValue("Text Entry");
}
// Save and close the filled out form.
pdfDocument.save("C:/FillFormField.pdf");
Currently dont have errors above code is working to fill out some junk fields.
need to fill exactly the Name with box info with Name information
Address with box info with Address information

Answer 1

I am able to do it with PDF Debugger from PDFBOX.
Used CMD prompt to get the structure of the file
java -jar pdfbox-app-1.8.10.jar PDFDebugger yourfile.pdf
please get the above jar file from apache PDF box.
once you able to see the structure, find the fields name.

Answer 2

For my purpose of locking, i dont need to use the encryption method. so used Acroform Flatten PDF method.
// flatten() method saves the PDF read only
acroForm.flatten();