Re: How can this abstract method error happen?

Hi.

This is my bad, sorry. I managed to be investigating on one system, where
the exception was happening on another. The actual system did have
a postgresql-9.1-903.jdbc3.jar in the classpath, hence the problem. So, the
answer to my original questions would be : Driver will never create
connection/statement objects of lesser JDBC version than what it's compiled
for (as Dave said), and, look better and you will find an older JDBC
Postgres driver in your classpath.

Tracing the code, it looks like it absolutely doesn't matter whether any
proxies are used to wrap the statement/connection obejcts. The proxy you
are seeing in the stack trace actually comes from Postgres driver, the
pooled connection object uses those. If the problem was with any of the
wrappers, the "AbstractMethodError", or an unrecognized method exception
would have been thrown from the wrapper, and not from Postgres object. All
the wrappers will have to, at the end, reference an actual
statement/connection object produced by the driver.

The version of JDBC used by core Java is also, IMHO, not important. Driver
will create whatever it considers "latest", since JDBC API is
backward-compatible, "extra" methods shouldn't cause any kind of issues. My
code assumes, and is compiled against, JDBC4, otherwise it wouldn't be
possible to call Statement.isClosed() which only exists in JDBC4.

Again, thank you, and sorry for the commotion.

On Wed, Jan 15, 2014 at 2:42 AM, Lachezar Dobrev <l(dot)dobrev(at)gmail(dot)com> wrote:

> Did you by chance include the PostgreSQL JDBC Driver with your application?
>
> The stack trace shows that the call passes through a Proxy class in
> some kind of cache. It seems to be Glassfish, which version?
>
> And did you try with a newer version of the JDBC Driver? 902 is a
> pinch older than the latest for 9.1 which is 903.
>
> Also note, that JDBC 4 is noted as incomplete.
>
> Also which JDBC version driver are you using? Which Java version?
>
> 2014/1/14 Pawel Veselov <pawel(dot)veselov(at)gmail(dot)com>:
> > Hi.
> >
> > I'm getting an abstract method error problem with Postgres JDBC (top of
> > exception trace:http://pastebin.com/xsDKSdiE). There isn't a stable way
> to
> > reproduce this that I found. The driver is 9.1-902.
> >
> > I don't quite understand how this can even happen. Looks like all the all
> > statement object are created by the connection object, and all connection
> > objects are created by the Driver. Driver always creates connection
> version
> > 4, and that connection always creates statements version 4, so it should
> > always implement isClosed(). I never ever used any earlier drivers (so I
> > don't think there is C/P mess up, but I grepped my class path too).
> >
> > Can anything else ever create a connection object, which can be of
> earlier
> > version?
> >
> > Thank you.
>