title: PDF itext TOC generation
body: <p>I have to merge multiple PDF documents into a single PDF document. Besides this, I have to generate TOC. The original documents will contain  text with a specific style (say H1). This special text becomes part of TOC. </p>
  
  <p>Have used iText for merging multiple PDF files. I am unable to find example/API on <strong>parsing the document to find all the contents having style H1</strong>. 
  Generating TOC is next challenge. </p>