com.aspose.words

Example:

Document doc = new Document();
DocumentBuilder builder = new DocumentBuilder(doc);

// We can use the section's PageSetup object to display numbers to the left of the section's text lines.
// This is the same behavior as a List object,
// but it covers the entire section and does not modify the text in any way.
// Our section will restart the numbering on each new page from 1 and display the number,
// if it is a multiple of 3, at 50pt to the left of the line.
PageSetup pageSetup = builder.getPageSetup();
pageSetup.setLineStartingNumber(1);
pageSetup.setLineNumberCountBy(3);
pageSetup.setLineNumberRestartMode(LineNumberRestartMode.RESTART_PAGE);
pageSetup.setLineNumberDistanceFromText(50.0d);

for (int i = 1; i <= 25; i++)
    builder.writeln(MessageFormat.format("Line {0}.", i));

// The line counter will skip any paragraph with the "SuppressLineNumbers" flag set to "true".
// This paragraph is on the 15th line, which is a multiple of 3, and thus would normally display a line number.
// The section's line counter will also ignore this line, treat the next line as the 15th,
// and continue the count from that point onward.
doc.getFirstSection().getBody().getParagraphs().get(14).getParagraphFormat().setSuppressLineNumbers(true);

doc.save(getArtifactsDir() + "PageSetup.LineNumbers.docx");