null line

基本解释

If not NULL, increment the line counter.
如果不是 NULL，则增加行计数器。
A serial line (null-modem cable) connects the machines through their serial ports.
一条串行线（空调制解调器电缆）将通过机器的串口连接它们。
When you modify the SimpleTask[] tasks = null; (line 2 in Listing 12) to SimpleTask[] tasks = new SimpleTasks[0];, you will only need to write Listing 13 to look like
当您将 SimpleTask[] tasks = null;（清单 12 中的第 2 行）修改为 SimpleTask[] tasks = new SimpleTasks[0]; 时，您只需将清单 13 编写为