ITextRenderer renderer = new ITextRenderer();
// we need to create the target PDF
// we'll create one page per input string, but we call layout for the first
renderer.setDocumentFromString(inputs[0]);
renderer.layout();
renderer.createPDF(os, false);
// each page after the first we add using layout() followed by writeNextDocument()
for (int i = 1; i < inputs.length; i++) {
renderer.setDocumentFromString(inputs[i]);