Question on Java Servlet to open a PDF file using iText -

the code below grabs pdf file , displays in browser.

import java.io.bytearrayoutputstream; import java.io.fileinputstream; import java.io.fileoutputstream; import java.io.ioexception; import java.io.inputstream; import java.io.inputstreamreader; import java.io.outputstream; import java.io.printwriter;  import javax.servlet.servletconfig; import javax.servlet.servletexception; import javax.servlet.http.httpservlet; import javax.servlet.http.httpservletrequest; import javax.servlet.http.httpservletresponse;  import com.lowagie.text.document; import com.lowagie.text.documentexception; import com.lowagie.text.pdf.pdfreader; import com.lowagie.text.pdf.pdfstamper; import com.lowagie.text.pdf.pdfstream; import com.lowagie.text.pdf.pdfwriter;  public class welcomeservlet extends httpservlet {      private static final string document_location = "h:\\testpdf.pdf"; // test pdf on pc      @override     public void init(servletconfig config) throws servletexception {         super.init(config);     }       protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {          bytearrayoutputstream baos = new bytearrayoutputstream();         pdfreader reader = new pdfreader(document_location);         pdfstamper stamper = null;         try {             stamper = new pdfstamper(reader, baos);         } catch (documentexception e) {             e.printstacktrace();         }         try {             stamper.close();         } catch (documentexception e) {             system.out.println("why making me this?");             e.printstacktrace();         }          // set response headers         response.setheader("expires", "0");         response.setheader("cache-control", "must-revalidate, post-check=0, pre-check=0");         response.setheader("pragma", "public");         response.setcontenttype("application/pdf");         response.setcontentlength(baos.size());          outputstream os = response.getoutputstream();         baos.writeto(os);         os.flush();         os.close();      } }  

if change code, doesn't return file. difference lines deal pdfstamper removed.

import java.io.bytearrayoutputstream;     import java.io.fileinputstream;     import java.io.fileoutputstream;     import java.io.ioexception;     import java.io.inputstream;     import java.io.inputstreamreader;     import java.io.outputstream;     import java.io.printwriter;      import javax.servlet.servletconfig;     import javax.servlet.servletexception;     import javax.servlet.http.httpservlet;     import javax.servlet.http.httpservletrequest;     import javax.servlet.http.httpservletresponse;      import com.lowagie.text.document;     import com.lowagie.text.documentexception;     import com.lowagie.text.pdf.pdfreader;     import com.lowagie.text.pdf.pdfstamper;     import com.lowagie.text.pdf.pdfstream;     import com.lowagie.text.pdf.pdfwriter;      public class welcomeservlet extends httpservlet {          private static final string document_location = "h:\\testpdf.pdf"; // test pdf on pc          @override         public void init(servletconfig config) throws servletexception {             super.init(config);         }           protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {              bytearrayoutputstream baos = new bytearrayoutputstream();             pdfreader reader = new pdfreader(document_location);              // set response headers             response.setheader("expires", "0");             response.setheader("cache-control", "must-revalidate, post-check=0, pre-check=0");             response.setheader("pragma", "public");             response.setcontenttype("application/pdf");             response.setcontentlength(baos.size());              outputstream os = response.getoutputstream();             baos.writeto(os);             os.flush();             os.close();          }     }  

why work pdfstamper? don't want stamping, want display pdf in browser. there i'm missing takes place of pdfstamper in itext???

when use pdfstamper reading in file disk , writing baos. when removed pdfstamper, baos never gets written to. of course, baos empty, never returns anything.

edit: want (the pdfreader necessary if want modify pdf):

private static void copy(inputstream is, outputstream os) throws ioexception {     byte buffer[] = new byte[8192];     int bytesread, i;      while ((bytesread = is.read(buffer)) != -1) {         os.write(buffer, 0, bytesread);     } } protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {              fileinputstream baos = new fileinputstream(document_location);              // set response headers             response.setheader("expires", "0");             response.setheader("cache-control", "must-revalidate, post-check=0, pre-check=0");             response.setheader("pragma", "public");             response.setcontenttype("application/pdf");             response.setcontentlength(new file(document_location).length());              outputstream os = response.getoutputstream();             copy(baos, os);             os.flush();             os.close();          }     }