code: private void continueExecution() {
          //increment task index
          i++;
          
          //submit next if the end of the chain not reached yet
          if (i < task.length && task[i] != null) {
          	scheduler.submit(task[i]);            
          } else if (listener != null) {
              listener.onTermination();
          }
      }
docs: Submits next task for the execution