//construct table
ITextTable textTable = textDocument.getTextTableService().
  constructTextTable(10, 5);       
textDocument.getTextService().getTextContentService().
  insertTextContent(textTable);

//Fill first 2 lines for header and format
String formatHeaderProp = "ParaStyleName";
String formatHeader = "Table Heading";
for(int i = 0, n = 2; i < n; i++) {
  for(int j = 0, m = textTable.getColumnCount(); j < m; j++) {
    IText cellText = textTable.getCell(j,i).getTextService().getText();
    cellText.setText("Header Line "+(i+1)+" Col "+(j+1));
    IParagraph paragraphs = cellText.getTextContentEnumeration().
      getParagraphs();
    for(int k = 0, s = paragraphs.length; k < s; k++) {
      paragraphs.getParagraphProperties().getXPropertySet().
        setPropertyValue(formatHeaderProp,formatHeader);
    }
  }
}