writing to file .....(java.io.tmpdir)

hi ...

i have a problem in writing the file to the temporary folder .....the file is not created ..if i give the path name by myself then the file is created .....
.
kindly anyone help me ....
Thanks in advance ....

MY CODING :

public void filewrite()
  {
 
        try {
           
                String temppath = new String(System.getProperty("java.io.tmpdir"));        
                String fileName = "temppath,outfile.txt";
                BufferedWriter out = new BufferedWriter(new FileWriter(fileName));
           
            out.write("DB_CONNECTION =   ");        
            out.write(DBConnection.getText());
            out.write("; ");
            out.write(DBname.getText());
            out.write("; ");
            out.write(Username.getText());
            out.write("; ");
            out.write(password.getPassword());            
            out.close();

        } catch (IOException e) {

            System.out.println("IOException:"+e);
            e.printStackTrace();

        }
  }