public static void mergeFiles(File[] files, File mergedFile) {

          FileWriter fstream = null;
          BufferedWriter out = null;
          try {
              fstream = new FileWriter(mergedFile, true);
               out = new BufferedWriter(fstream);
          } catch (IOException e1) {
              e1.printStackTrace();
          }

          for (File f : files) {
              System.out.println("merging: " + f.getName());
              FileInputStream fis;
              try {
                   fis = new FileInputStream(f);
                   BufferedReader in = new BufferedReader(new InputStreamReader(fis));

                   String aLine;
                   while ((aLine = in.readLine()) != null) {
                        out.write(aLine);
                        out.newLine();
                   }

                   in.close();
              } catch (IOException e) {
                   e.printStackTrace();
              }
          }

          try {
              out.close();
          } catch (IOException e) {
              e.printStackTrace();
          }

     }

    public static void main(String[] args) {
          String sourceFile1Path = "file1.txt";
          String sourceFile2Path = "file2.txt";

          String mergedFilePath = "merge.txt";

          File[] files = new File[2];
          files[0] = new File(sourceFile1Path);
          files[1] = new File(sourceFile2Path);

          File mergedFile = new File(mergedFilePath);

          mergeFiles(files, mergedFile);
     }