java.sql.SQLException: No operations allowed after connection closed . DB: mysql

Question

Exception : java.sql.SQLException: No operations allowed after connection closed.

I got this strange exception when I tried to run my application. I am using local variable for connection object and after execution of some statements this exception is raising. I am using c3p0 connection pool and MySQL database.

Answer 1

It is difficult to diagnose this without seeing your code, but I once had an similar problem due to the fact that mysql closes the connections after a while; so make sure that the configuration of your datasource has a validation query, and testOnBorrow and testWhileIdle are both true.

Here is an example:

    <Resource auth="Container" type="javax.sql.DataSource" name="jdbc/mydb"
            driverClassName="com.mysql.jdbc.Driver"
            url="jdbc:mysql://myserver/mydb"
            maxActive="10"
            maxIdle="5"
            validationQuery="SELECT 1"
            testOnBorrow="true"
            testWhileIdle="true"
            timeBetweenEvictionRunsMillis="10000"
            minEvictableIdleTimeMillis="60000"
            username="???" password="???"/>