Oracle错误解决：ORA-12519, TNS:no appropriate service handler found

问题：java.sql.SQLException: Listener refused the connection with the following error:

ORA-12519, TNS:no appropriate service handlerfound

解决：超过连接数，所以要扩大。在oracle中执行sql语句

select value from v$parameter where name ='processes'; 取得进程数的上限。

alter system set processes = 300 scope =spfile; 重新设置连接数

alter system set sessions=335 scope=spfile; 设置SESSIONS = PROCESSES * 1.1 + 5

重启数据库:
shutdown immediate;
startup;