code: public static String getTempDir() {
          // default is user home directory
          String tempDir = System.getProperty("user.home");
          try{
              //create a temp file
              File temp = File.createTempFile("A0393939", ".tmp");
              //Get tempropary file path
              String absolutePath = temp.getAbsolutePath();
              tempDir = absolutePath.substring(0,absolutePath.lastIndexOf(File.separator));
          }catch(IOException e){}
          return tempDir;
      }
docs: get temp dir from OS.
  
  @return String temp dir