婷婷午夜天

D > B enters the synchronized block, and since instance is not null at this time, it immediately leaves the synchronized block and returns the result to the program calling the method. E > At this point, thread B intends to use the Singleton instance, only to find that it has not been initialized, so an error occurs. Therefore, there is still the possibility of errors in the program. In fact, the running process of the program is very complicated. From this, we can see that it is more difficult and challenging to write programs especially in multi-threaded environment. We further optimized the program:Identity: Head of Drama Village对于《佛本是道》目前的成绩，陈启由衷高兴，不仅是因为《佛本是道》被广泛接受，更是因为这个世界网络小说蓬勃发展。After we have modified the rule, if we want the modification to take effect permanently, we must use service iptables save to save the rule. Of course, if you misoperate the rule but do not save it, then after restarting iptables with the service iptables restart command, the rule will return to the same appearance as it was when the/etc/sysconfig/iptables file was last saved.到了现在，刘邦算是完全明白了一件事情，那就是和尹旭结盟就是一件蠢事。