code: private synchronized void submit(final String command) {
      LOG.log(Level.INFO, "Submit command {0} to {1} evaluators. state: {2}",
          new Object[]{command, this.contexts.size(), this.state});
      assert this.state == State.READY;
      this.expectCount = this.contexts.size();
      this.state = State.WAIT_TASKS;
      this.cmd = null;
      for (final ActiveContext context : this.contexts.values()) {
        this.submit(context, command);
      }
    }
docs: Submit command to all available evaluators.
  
  @param command shell command to execute.