com.aspose.words

Example:

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

// Line numbering for each section can be configured via PageSetup
PageSetup pageSetup = builder.getPageSetup();
pageSetup.setLineStartingNumber(1);
pageSetup.setLineNumberCountBy(3);
pageSetup.setLineNumberRestartMode(LineNumberRestartMode.RESTART_PAGE);
pageSetup.setLineNumberDistanceFromText(50.0d);

// LineNumberCountBy is set to 3, so every line that's a multiple of 3
// will display that line number to the left of the text
for (int i = 1; i <= 25; i++)
    builder.writeln(MessageFormat.format("Line {0}.", i));

// The line counter will skip any paragraph with this flag set to true
// Normally, the number "15" would normally appear next to this paragraph, which says "Line 15"
// Since we set this flag to true and this paragraph is not counted by numbering,
// number 15 will appear next to the next paragraph, "Line 16", and from then on counting will carry on as normal
// until it will restart according to LineNumberRestartMode
doc.getFirstSection().getBody().getParagraphs().get(14).getParagraphFormat().setSuppressLineNumbers(true);

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