com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection, message from server: Too many connections
最简单的办法是因为你的my.ini中设定的并发连接数太少或者系统繁忙导致连接数被占满解决方式：打开MySQL安装目录打开MY.INI找到max_connections默认是100.--实例WINDOWS解决mysql Errno.:1040错误XXXXinfo:CannotconnecttoMySQLserv...
CountDownLatch是什么？
CountDownLatch是Java中一个同步工具类，用于控制多个线程的执行顺序。它可以让某个线程一直等待，直到其他线程完成各自的操作后再继续执行。CountDownLatch通过一个计数器来实现，计数器的初始值为线程数量，每当一个线程完成任务后，计数器的值就会减1，当计数器的值变为0时，等待的线程就会被唤醒继续执行...
ORA-25228: timeout or end-of-fetch during message dequeue from string.string
文档解释ORA-25228:timeoutorend-of-fetchduringmessagedequeuefromstring.stringCause:User-specifieddequeuewaittimehaspassedortheendofthequeuehasbeenreachedbutnomessage...
ORA-16416: No viable stringswitchover targets available
文档解释ORA-16416:NoviablestringswitchovertargetsavailableCause:Switchoverfailedbecausenostandbydatabasesoftheappropriatetypewereavailable.Action:Checkthealertlogfo...
ORA-21524: object type mismatch
文档解释ORA-21524:objecttypemismatchCause:Theobjecttypeoftheobjectisdifferentfromwhatisspecified.Action:Checkthetypeoftheobjectandcorrectit.OORA-21524:objecttypemis...