看一下Java线程状态:
NEW
A thread that has not yet started is in this state.
RUNNABLE
A thread executing in the Java virtual machine is in this state.
BLOCKED
A thread that is blocked waiting for a monitor lock is in this state.
WAITING
A thread that is waiting indefinitely for another thread to perform a particular action is in this state.
TIMED_WAITING
A thread that is waiting for another thread to perform an action for up to a specified waiting time is in this state.
TERMINATED
A thread that has exited is in this state.
为什么没有空闲状态?或者什么状态最接近于空闲线程?RUNNING只是不在CPU上执行吗?
撇开NEW和TERMINATED不谈，"idle"的意思是"等待东西"。这包括以下所有内容:
BLOCKED
WAITING
TIMED_WAITING
是
RUNNING，但只是不执行CPU?
没有RUNNING，只有RUNNABLE。这大致意味着"有事情要做"，但没有说明线程现在是否正在运行(它可能正在等待一个核心可用)。
阻塞线程是调用慢速和/或共享资源的线程。因为在调用返回之前线程不能继续，所以线程是空闲的。
WAITING and time_waiting是指线程正在等待另一个线程(而不是某些资源)，并且在另一个线程允许它恢复之前将处于空闲状态。
NEW只是还没有在CPU上调度。它本质上是RUNNABLE，但这指出了它刚刚被创建的事实。我个人不会认为这是徒劳的。
RUNNABLE表示正在运行，或者正在等待分配给CPU。