java - FileOutputStream appending issue, where I am going wrong? -

i trying 3 5 pdf file(from internet source) & merging them 1 after another. fyi, dont want use itext or other pdf lib, because, please @ code once

public static void savefile(string[] urls, string filename) throws ioexception {     clienturlconnection clienturlconnection = null;     inputstream inputstream = null;     try {         int t = 1;         fileoutputstream outputstream = new fileoutputstream(filename,true);         (string url : urls) {                             clienturlconnection = new clienturlconnection(url);             clienturlconnection.sethttpmethod(clienturlconnection.get_method);             inputstream = clienturlconnection.getinputstream();             outputstream.write(ioutils.tobytearray(inputstream));             inputstream.close();             outputstream.flush();             system.out.println((t++) + " - file inserted in " + filename + "\n");             thread.sleep(3000);         }             outputstream.close();     } catch (exception ex) {         ex.printstacktrace();     } } 

string[] urls - array of url's pdf document. sting filename - single file store pdf's in it. clienturlconnecion - own class handle proxy , other things.

expected output - 2 pdf's urls in single file

actual output - second pdf overwriting first one, size of file sum of size of 2 pdf's.

problem - made fileoutputstream - append true, overwriting. don't understand i'm doing wrong

thanks in advance

merging 2 pdf files not equivalent appending binary content of files.

your code may append bytes way want -as suggests size of output file-, seems last appended file read pdf reader when open it.

therefore, probably should use api read actual content of pdf.