Thread 退出条件

• run 方法执行完毕
• run 方法抛异常

JVM 退出条件

• When a Java Virtual Machine starts up, there is usually a single non-daemon thread (which typically calls the method named main of some designated class). The Java Virtual Machine continues to execute threads until either of the following occurs:
  • The exit method of class Runtime has been called and the security manager has permitted the exit operation to take place.
  • All threads that are not daemon threads have died, either by returning from the call to the run method or by throwing an exception that propagates beyond the run method.
• 当没有用户线程执行的时候
• 在任何线程调用 System.exit 会导致退出