Re: first connection attempt always fails, subsequent always succeed

Bingo.  I have that in one servlet, the writer, whose code pre-dates the readers.  I’ll push that down one class.
Thanks so much.


> On Nov 12, 2020, at 1:42 PM, Mark Rotteveel <mark@lawinegevaar.nl> wrote:
>
> On 12-11-2020 20:31, Rob Sargent wrote:
>> thinking these forums like bottom posting
>> From my war file (which I explode)
>>    WEB-INF/lib/postgresql-42.2.18.jar
>
> If the JDBC driver is included in the WAR, then you need to explicitly load the driver with
`Class.forName("org.postgresql.Driver")`,because automatic driver loading doesn't work when the driver is on an web
applicationclasspath; it will only work if the driver is on the initial classpath (ie in Tomcats lib folder). 
>
> The second attempt likely works because you or your code did something that triggered the driver to load (ie directly
orindirectly loading the org.postgresql.Driver class). 
>
> That said, using `DriverManager.getConnection` in a web application is generally not a good idea. For performance it
isusually better to use a connection pool (eg the one built-in in Tomcat, or a third-party lib like HikariCP). 
>
> Mark
> --
> Mark Rotteveel
>
>