Thread: [JDBC] old JDBC driver (8.1-JDBC3) can connect to postgresql 9.x ?

Hi exports,

Thanks for your great effort and works for JDBC drivers.
Now I have one question.

  (Q) Can the old JDBC driver(8.1-404 JDBC3) connect to latest or supported versions(greater than 9.1) of postgresql ??

We would be happy if we have an answerfor this because of the background below although it's not supported version
currently...
I hope that postgresql 9.x can handle V3 JDBC protocols even if a versions of jdbc3 driver on clients is old.

  Background:
    - Our old web application is running on JVM 1.5 + tomcat5 + JDBC driver(8.1-404-JDBC3) + postgresql 8.3.22
    - Now we plan to get to connect the application to postgresql 9.x(setup newly) in addition to the existing
postgresql8.3.22. 

Thanks and best regards,
itoshun

efeel web administrater

Hi Jorge

Thank you much for your quick reply !
Now I understand the new JDBC driver (9.3 Build 1103) will work with postgresql 8.3 and 9.3.

I have an additional question (sorry for my sticky question)

  (Q) We would be happy if we can use the old jdbc driver(8.1-404 JDBC3) also to postgresql 9.3.
      Is it possible technically ?
      (I know it's not supported version and might have problems fixed by later versions)

I ask this because:
  - the old jdbc driver is stable for existing functions on our web app
  - the number of existing functions affected by upgrading a JDBC driver is so large on our web app

Now many existing functions are connecting to postgresql 8.3 with the old jdbc driver on our web app and in the near
futurewe will connect a few new functions to postgresql 9.1. 
Then upgrading jdbc driver needs many tests and using old jdbc driver also to postgresql 9.1 needs a few tests.

Sorry to be so demanding .... and thank you for your kindness.


Best regards,
itoshun


----- Original Message -----
>From: Jorge Solórzano <jorsol@gmail.com>
>To: "itoshun001@efeel.to" <itoshun001@efeel.to>
>Cc: "pgsql-jdbc@postgresql.org" <pgsql-jdbc@postgresql.org>
>Date: 2017/1/16, Mon 22:32
>Subject: Re: [JDBC] old JDBC driver (8.1-JDBC3) can connect to postgresql 9.x ?
>
>
>The last version that supported Java 5 is 9.3 Build 1103, so you should use that version and it will work with
postgresql8.3 and postgresql 9.3. 
>
>
>
>Jorge Solórzano
>
>
>On Mon, Jan 16, 2017 at 1:05 AM, itoshun001@efeel.to <itoshun001@efeel.to> wrote:
>
>Hi exports,
>>
>>Thanks for your great effort and works for JDBC drivers.
>>Now I have one question.
>>
>>  (Q) Can the old JDBC driver(8.1-404 JDBC3) connect to latest or supported versions(greater than 9.1) of postgresql
??
>>
>>We would be happy if we have an answerfor this because of the background below although it's not supported version
currently...
>>I hope that postgresql 9.x can handle V3 JDBC protocols even if a versions of jdbc3 driver on clients is old.
>>
>>  Background:
>>    - Our old web application is running on JVM 1.5 + tomcat5 + JDBC driver(8.1-404-JDBC3) + postgresql 8.3.22
>>    - Now we plan to get to connect the application to postgresql 9.x(setup newly) in addition to the existing
postgresql8.3.22. 
>>
>>Thanks and best regards,
>>itoshun
>>
>>efeel web administrater
>>
>>
>>--
>>Sent via pgsql-jdbc mailing list (pgsql-jdbc@postgresql.org)
>>To make changes to your subscription:
>>http://www.postgresql.org/ mailpref/pgsql-jdbc
>>
>
>
>

Hi Jorge

Thank you much for your quick reply !
Now I understand the new JDBC driver (9.3 Build 1103) will work with postgresql 8.3 and 9.3.

I have an additional question (sorry for my sticky question)

  (Q) We would be happy if we can use the old jdbc driver(8.1-404 JDBC3) also to postgresql 9.3.
      Is it possible technically ?
      (I know it's not supported version and might have problems fixed by later versions)

I ask this because:
  - the old jdbc driver is stable for existing functions on our web app
  - the number of existing functions affected by upgrading a JDBC driver is so large on our web app

Now many existing functions are connecting to postgresql 8.3 with the old jdbc driver on our web app and in the near
futurewe will connect a few new functions to postgresql 9.1. 
Then upgrading jdbc driver needs many tests and using old jdbc driver also to postgresql 9.1 needs a few tests.

Sorry to be so demanding .... and thank you for your kindness.


Best regards,
itoshun


----- Original Message -----
>From: Jorge Solórzano <jorsol@gmail.com>
>To: "itoshun001@efeel.to" <itoshun001@efeel.to>
>Cc: "pgsql-jdbc@postgresql.org" <pgsql-jdbc@postgresql.org>
>Date: 2017/1/16, Mon 22:32
>Subject: Re: [JDBC] old JDBC driver (8.1-JDBC3) can connect to postgresql 9.x ?
>
>
>The last version that supported Java 5 is 9.3 Build 1103, so you should use that version and it will work with
postgresql8.3 and postgresql 9.3. 
>
>
>
>Jorge Solórzano
>
>
>On Mon, Jan 16, 2017 at 1:05 AM, itoshun001@efeel.to <itoshun001@efeel.to> wrote:
>
>Hi exports,
>>
>>Thanks for your great effort and works for JDBC drivers.
>>Now I have one question.
>>
>>  (Q) Can the old JDBC driver(8.1-404 JDBC3) connect to latest or supported versions(greater than 9.1) of postgresql
??
>>
>>We would be happy if we have an answerfor this because of the background below although it's not supported version
currently...
>>I hope that postgresql 9.x can handle V3 JDBC protocols even if a versions of jdbc3 driver on clients is old.
>>
>>  Background:
>>    - Our old web application is running on JVM 1.5 + tomcat5 + JDBC driver(8.1-404-JDBC3) + postgresql 8.3.22
>>    - Now we plan to get to connect the application to postgresql 9.x(setup newly) in addition to the existing
postgresql8.3.22. 
>>
>>Thanks and best regards,
>>itoshun
>>
>>efeel web administrater
>>
>>
>>--
>>Sent via pgsql-jdbc mailing list (pgsql-jdbc@postgresql.org)
>>To make changes to your subscription:
>>http://www.postgresql.org/ mailpref/pgsql-jdbc
>>
>
>
>

Hi Jorge

Thank you for your accurate answers and kind understanding for our situation.
Now I understand below and these info is very useful for our team !

  - the old driver(8.1-404 JDBC3) technically can connect to postgresql 9.3 but some new features should not be
available,and we won't get the bugfixes of later version. 

  - the driver should be highly compatible with earlier versions, and if our web app is using standard jdbc, then it
shouldbe practically transparent the change (we don't even need to recompile). 

One more question which might be last question....

  (Q) My understanding below is correct ??

      Versions of jdbc driver that supported Java 5 can't connect to postgresql 9.4 or later 
      because 
       - the versions of jdbc driver don't support JDBC 4, 41 and 42
       - the versions of postreqsql don't support JDBC3

Best regards,
itoshun


----- Original Message -----
>From: Jorge Solórzano <jorsol@gmail.com>
>To: "itoshun001@efeel.to" <itoshun001@efeel.to>
>Cc: "pgsql-jdbc@postgresql.org" <pgsql-jdbc@postgresql.org>
>Date: 2017/1/17, Tue 08:21
>Subject: Re: [JDBC] old JDBC driver (8.1-JDBC3) can connect to postgresql 9.x ?
>
>
>On Mon, Jan 16, 2017 at 4:41 PM, itoshun001@efeel.to <itoshun001@efeel.to> wrote:
>
>Hi Jorge
>>
>>Thank you much for your quick reply !
>>Now I understand the new JDBC driver (9.3 Build 1103) will work with postgresql 8.3 and 9.3.
>>
>>I have an additional question (sorry for my sticky question)
>>
>>  (Q) We would be happy if we can use the old jdbc driver(8.1-404 JDBC3) also to postgresql 9.3.
>>      Is it possible technically ?
>>      (I know it's not supported version and might have problems fixed by later versions)
>>
>
>​Yes, it is technically possible but some new features should not be available, and you wont get the bugfixes of later
version.
>
>
>
>>I ask this because:
>>  - the old jdbc driver is stable for existing functions on our web app
>>  - the number of existing functions affected by upgrading a JDBC driver is so large on our web app
>>
>
>​The driver should be highly compatible with earlier versions, and if your web app is using standard jdbc, then it
shouldbe practically transparent the change (you don't even need to recompile). 
>
>
>
>>Now many existing functions are connecting to postgresql 8.3 with the old jdbc driver on our web app and in the near
futurewe will connect a few new functions to postgresql 9.1. 
>>Then upgrading jdbc driver needs many tests and using old jdbc driver also to postgresql 9.1 needs a few tests.
>>
>
>
>As as usual a proper testing prior to production should get you the idea if it will break something.​
> 
>
>>Sorry to be so demanding .... and thank you for your kindness.
>>
>>
>>Best regards,
>>itoshun
>>
>>
>>
>>----- Original Message -----
>>>From: Jorge Solórzano <jorsol@gmail.com>
>>>To: "itoshun001@efeel.to" <itoshun001@efeel.to>
>>>Cc: "pgsql-jdbc@postgresql.org" <pgsql-jdbc@postgresql.org>
>>>Date: 2017/1/16, Mon 22:32
>>>Subject: Re: [JDBC] old JDBC driver (8.1-JDBC3) can connect to postgresql 9.x ?
>>>
>>>
>>>The last version that supported Java 5 is 9.3 Build 1103, so you should use that version and it will work with
postgresql8.3 and postgresql 9.3. 
>>>
>>>
>>>
>>>Jorge Solórzano
>>>
>>>
>>>On Mon, Jan 16, 2017 at 1:05 AM, itoshun001@efeel.to <itoshun001@efeel.to> wrote:
>>>
>>>Hi exports,
>>>>
>>>>Thanks for your great effort and works for JDBC drivers.
>>>>Now I have one question.
>>>>
>>>>  (Q) Can the old JDBC driver(8.1-404 JDBC3) connect to latest or supported versions(greater than 9.1) of
postgresql?? 
>>>>
>>>>We would be happy if we have an answerfor this because of the background below although it's not supported version
currently...
>>>>I hope that postgresql 9.x can handle V3 JDBC protocols even if a versions of jdbc3 driver on clients is old.
>>>>
>>>>  Background:
>>>>    - Our old web application is running on JVM 1.5 + tomcat5 + JDBC driver(8.1-404-JDBC3) + postgresql 8.3.22
>>>>    - Now we plan to get to connect the application to postgresql 9.x(setup newly) in addition to the existing
postgresql8.3.22. 
>>>>
>>>>Thanks and best regards,
>>>>itoshun
>>>>
>>>>efeel web administrater
>>>>
>>>>
>>>>--
>>>>Sent via pgsql-jdbc mailing list (pgsql-jdbc@postgresql.org)
>>>>To make changes to your subscription:
>>>>http://www.postgresql.org/ mailpref/pgsql-jdbc
>>>>
>>>
>>>
>>>
>>
>
>
>

Hi Jorge

Thank you for your accurate answers and kind understanding for our situation.
Now I understand below and these info is very useful for our team !

  - the old driver(8.1-404 JDBC3) technically can connect to postgresql 9.3 but some new features should not be
available,and we won't get the bugfixes of later version. 

  - the driver should be highly compatible with earlier versions, and if our web app is using standard jdbc, then it
shouldbe practically transparent the change (we don't even need to recompile). 

One more question which might be last question....

  (Q) My understanding below is correct ??

      Versions of jdbc driver that supported Java 5 can't connect to postgresql 9.4 or later 
      because 
       - the versions of jdbc driver don't support JDBC 4, 41 and 42
       - the versions of postreqsql don't support JDBC3

Best regards,
itoshun


----- Original Message -----
>From: Jorge Solórzano <jorsol@gmail.com>
>To: "itoshun001@efeel.to" <itoshun001@efeel.to>
>Cc: "pgsql-jdbc@postgresql.org" <pgsql-jdbc@postgresql.org>
>Date: 2017/1/17, Tue 08:21
>Subject: Re: [JDBC] old JDBC driver (8.1-JDBC3) can connect to postgresql 9.x ?
>
>
>On Mon, Jan 16, 2017 at 4:41 PM, itoshun001@efeel.to <itoshun001@efeel.to> wrote:
>
>Hi Jorge
>>
>>Thank you much for your quick reply !
>>Now I understand the new JDBC driver (9.3 Build 1103) will work with postgresql 8.3 and 9.3.
>>
>>I have an additional question (sorry for my sticky question)
>>
>>  (Q) We would be happy if we can use the old jdbc driver(8.1-404 JDBC3) also to postgresql 9.3.
>>      Is it possible technically ?
>>      (I know it's not supported version and might have problems fixed by later versions)
>>
>
>​Yes, it is technically possible but some new features should not be available, and you wont get the bugfixes of later
version.
>
>
>
>>I ask this because:
>>  - the old jdbc driver is stable for existing functions on our web app
>>  - the number of existing functions affected by upgrading a JDBC driver is so large on our web app
>>
>
>​The driver should be highly compatible with earlier versions, and if your web app is using standard jdbc, then it
shouldbe practically transparent the change (you don't even need to recompile). 
>
>
>
>>Now many existing functions are connecting to postgresql 8.3 with the old jdbc driver on our web app and in the near
futurewe will connect a few new functions to postgresql 9.1. 
>>Then upgrading jdbc driver needs many tests and using old jdbc driver also to postgresql 9.1 needs a few tests.
>>
>
>
>As as usual a proper testing prior to production should get you the idea if it will break something.​
> 
>
>>Sorry to be so demanding .... and thank you for your kindness.
>>
>>
>>Best regards,
>>itoshun
>>
>>
>>
>>----- Original Message -----
>>>From: Jorge Solórzano <jorsol@gmail.com>
>>>To: "itoshun001@efeel.to" <itoshun001@efeel.to>
>>>Cc: "pgsql-jdbc@postgresql.org" <pgsql-jdbc@postgresql.org>
>>>Date: 2017/1/16, Mon 22:32
>>>Subject: Re: [JDBC] old JDBC driver (8.1-JDBC3) can connect to postgresql 9.x ?
>>>
>>>
>>>The last version that supported Java 5 is 9.3 Build 1103, so you should use that version and it will work with
postgresql8.3 and postgresql 9.3. 
>>>
>>>
>>>
>>>Jorge Solórzano
>>>
>>>
>>>On Mon, Jan 16, 2017 at 1:05 AM, itoshun001@efeel.to <itoshun001@efeel.to> wrote:
>>>
>>>Hi exports,
>>>>
>>>>Thanks for your great effort and works for JDBC drivers.
>>>>Now I have one question.
>>>>
>>>>  (Q) Can the old JDBC driver(8.1-404 JDBC3) connect to latest or supported versions(greater than 9.1) of
postgresql?? 
>>>>
>>>>We would be happy if we have an answerfor this because of the background below although it's not supported version
currently...
>>>>I hope that postgresql 9.x can handle V3 JDBC protocols even if a versions of jdbc3 driver on clients is old.
>>>>
>>>>  Background:
>>>>    - Our old web application is running on JVM 1.5 + tomcat5 + JDBC driver(8.1-404-JDBC3) + postgresql 8.3.22
>>>>    - Now we plan to get to connect the application to postgresql 9.x(setup newly) in addition to the existing
postgresql8.3.22. 
>>>>
>>>>Thanks and best regards,
>>>>itoshun
>>>>
>>>>efeel web administrater
>>>>
>>>>
>>>>--
>>>>Sent via pgsql-jdbc mailing list (pgsql-jdbc@postgresql.org)
>>>>To make changes to your subscription:
>>>>http://www.postgresql.org/ mailpref/pgsql-jdbc
>>>>
>>>
>>>
>>>
>>
>
>
>

On 1/16/2017 4:05 PM, itoshun001@efeel.to wrote:
>        Versions of jdbc driver that supported Java 5 can't connect to postgresql 9.4 or later
>        because
>         - the versions of jdbc driver don't support JDBC 4, 41 and 42
>         - the versions of postreqsql don't support JDBC3

java 5 is obsolete and no longer supported, so the postgres jdbc driver
no longer goes to the extra effort of testing to support it.

postgresql itself knows nothing about jdbc any version, thats purely
between Java and the JDBC driver.

the major issue I can see that you might hit using an old jdbc driver
with a much newer postgres database server is catalog changes...  the
old driver was written with an understanding of pg_catalog circa
postgres 8.1 or 8.3...    some things have changed, the new version
supports both new and old catalog changes.    the other potential issue
is somewhere around 8.4 or 9.0, postgresql got stricter on automatic
datatype casting, and there are certain implicit type casts that would
work in 8.x that no longer work.   I do forget exact version this happened.


--
john r pierce, recycling bits in santa cruz

On 1/16/2017 4:05 PM, itoshun001@efeel.to wrote:
>        Versions of jdbc driver that supported Java 5 can't connect to postgresql 9.4 or later
>        because
>         - the versions of jdbc driver don't support JDBC 4, 41 and 42
>         - the versions of postreqsql don't support JDBC3

java 5 is obsolete and no longer supported, so the postgres jdbc driver
no longer goes to the extra effort of testing to support it.

postgresql itself knows nothing about jdbc any version, thats purely
between Java and the JDBC driver.

the major issue I can see that you might hit using an old jdbc driver
with a much newer postgres database server is catalog changes...  the
old driver was written with an understanding of pg_catalog circa
postgres 8.1 or 8.3...    some things have changed, the new version
supports both new and old catalog changes.    the other potential issue
is somewhere around 8.4 or 9.0, postgresql got stricter on automatic
datatype casting, and there are certain implicit type casts that would
work in 8.x that no longer work.   I do forget exact version this happened.


--
john r pierce, recycling bits in santa cruz

Hi Jorge and John

Thank you so much for your kind explanations in spite of questions about obsoleted versions of JVM and not supported
versionsof JDBC driver  

Now I have understood risks to use old version of JDBC driver such as a schema catalog change.
Then we will try not to use old version of JDBC to connect to postgresql 9.x.

Thanks much and best regards,
itoshun
----- Original Message -----
>From: Jorge Solórzano <jorsol@gmail.com>
>To: "itoshun001@efeel.to" <itoshun001@efeel.to>
>Cc: "pgsql-jdbc@postgresql.org" <pgsql-jdbc@postgresql.org>
>Date: 2017/1/17, Tue 11:02
>Subject: Re: [JDBC] old JDBC driver (8.1-JDBC3) can connect to postgresql 9.x ?
>
>
>
>
>On Mon, Jan 16, 2017 at 6:05 PM, itoshun001@efeel.to <itoshun001@efeel.to> wrote:
>
>Hi Jorge
>>
>>Thank you for your accurate answers and kind understanding for our situation.
>>Now I understand below and these info is very useful for our team !
>>
>>  - the old driver(8.1-404 JDBC3) technically can connect to postgresql 9.3 but some new features should not be
available,and we won't get the bugfixes of later version. 
>>
>
>
>​Yes technically, but as John points out ​you could hit a schema catalog change so while it *might* work, there is a
chanceto hit a problem with pg_catalog updates, the pg_catalog is an internal postgresql table that contains many info
consumedby the pgjdbc driver and newer versions of the driver can handle all these variations, so for instance the
pgjdbcdriver 9.3 Build 1103 can connect without problems to older postgresql versions like the one you are using (8.3)
andit can connect to newer postgresql versions like 9.3. 
>
>For many years the pgjdbc driver followed the versions of the server to declare some kind of compatibility, basically
itmeans that the version you are using (8.1-404 JDBC3) was essentially for postgresql 8.1 and older, but you are using
itfor postgresql 8.3 and it works (for you). From the version 9.4.x of the driver that is no longer the case, and the
currentversion 9.4.1212 works on PostgreSQL 9.6 too. 
>
> 
>
>>  - the driver should be highly compatible with earlier versions, and if our web app is using standard jdbc, then it
shouldbe practically transparent the change (we don't even need to recompile). 
>>
>
>
>Yes, it should work for postgresql 8.3 and postgresql 9.3 (and everything between) that means that you should be using
(basedon the Java 5 version) the PgJDBC 9.3 Build 1103 and not the 8.1-404, but as I said before, always test for
potentialregressions. 
>
> 
>
>>One more question which might be last question....
>>
>>  (Q) My understanding below is correct ??
>>
>>      Versions of jdbc driver that supported Java 5 can't connect to postgresql 9.4 or later 
>>      because 
>>       - the versions of jdbc driver don't support JDBC 4, 41 and 42
>>       - the versions of postreqsql don't support JDBC3
>>
>
>
>​​Let me be cristal clear​, it *might* work ​but again, you might hit a problem with pg_catalog updates and others
compatibilityissues, so is NOT recomeded to use an older driver version to connect to a newer postgresql version, you
shouldalways try to use the latest driver. For example I have a web app that is still on PostgreSQL 9.1 but it's using
thelatest driver version 9.4.1212. What I mean is that is better to have a new jdbc driver connecting to an older
postgresqlinstance than the opposite. 
>
>
>To clarify your points, PostgreSQL knows nothing about Java or JDBC, the PgJDBC driver is a pure Java driver that
implementsthe native protocol of PostgreSQL, so PgJDBC "talks" in the PostgreSQL native language (the binary or text
protocolthat postgres understand). So when a new version of PostgreSQL comes out, the driver has to "understand" the
newor changed stuff so an older version of the driver do not recognize the changed stuff and there might hit a
compatibilityissue. 
>
>
>And as John said, Java 5 is obsolete, my recomendation is to try upgrading the Java version, at least to Java 6, Java
isfor the most part backward compatible, so you can use a new Java Runtime for a Java 5 compiled app. 
>
>
>Then try to update the PgJDBC driver to the latest version, and finally try to upgrade the PostgreSQL server to a
supportedversion. 
>
>
>As always, test, test and do more test for any potential problem.
>
> 
>
>>Best regards,
>>itoshun
>>
>
>

Hi Jorge and John

Thank you so much for your kind explanations in spite of questions about obsoleted versions of JVM and not supported
versionsof JDBC driver  

Now I have understood risks to use old version of JDBC driver such as a schema catalog change.
Then we will try not to use old version of JDBC to connect to postgresql 9.x.

Thanks much and best regards,
itoshun
----- Original Message -----
>From: Jorge Solórzano <jorsol@gmail.com>
>To: "itoshun001@efeel.to" <itoshun001@efeel.to>
>Cc: "pgsql-jdbc@postgresql.org" <pgsql-jdbc@postgresql.org>
>Date: 2017/1/17, Tue 11:02
>Subject: Re: [JDBC] old JDBC driver (8.1-JDBC3) can connect to postgresql 9.x ?
>
>
>
>
>On Mon, Jan 16, 2017 at 6:05 PM, itoshun001@efeel.to <itoshun001@efeel.to> wrote:
>
>Hi Jorge
>>
>>Thank you for your accurate answers and kind understanding for our situation.
>>Now I understand below and these info is very useful for our team !
>>
>>  - the old driver(8.1-404 JDBC3) technically can connect to postgresql 9.3 but some new features should not be
available,and we won't get the bugfixes of later version. 
>>
>
>
>​Yes technically, but as John points out ​you could hit a schema catalog change so while it *might* work, there is a
chanceto hit a problem with pg_catalog updates, the pg_catalog is an internal postgresql table that contains many info
consumedby the pgjdbc driver and newer versions of the driver can handle all these variations, so for instance the
pgjdbcdriver 9.3 Build 1103 can connect without problems to older postgresql versions like the one you are using (8.3)
andit can connect to newer postgresql versions like 9.3. 
>
>For many years the pgjdbc driver followed the versions of the server to declare some kind of compatibility, basically
itmeans that the version you are using (8.1-404 JDBC3) was essentially for postgresql 8.1 and older, but you are using
itfor postgresql 8.3 and it works (for you). From the version 9.4.x of the driver that is no longer the case, and the
currentversion 9.4.1212 works on PostgreSQL 9.6 too. 
>
> 
>
>>  - the driver should be highly compatible with earlier versions, and if our web app is using standard jdbc, then it
shouldbe practically transparent the change (we don't even need to recompile). 
>>
>
>
>Yes, it should work for postgresql 8.3 and postgresql 9.3 (and everything between) that means that you should be using
(basedon the Java 5 version) the PgJDBC 9.3 Build 1103 and not the 8.1-404, but as I said before, always test for
potentialregressions. 
>
> 
>
>>One more question which might be last question....
>>
>>  (Q) My understanding below is correct ??
>>
>>      Versions of jdbc driver that supported Java 5 can't connect to postgresql 9.4 or later 
>>      because 
>>       - the versions of jdbc driver don't support JDBC 4, 41 and 42
>>       - the versions of postreqsql don't support JDBC3
>>
>
>
>​​Let me be cristal clear​, it *might* work ​but again, you might hit a problem with pg_catalog updates and others
compatibilityissues, so is NOT recomeded to use an older driver version to connect to a newer postgresql version, you
shouldalways try to use the latest driver. For example I have a web app that is still on PostgreSQL 9.1 but it's using
thelatest driver version 9.4.1212. What I mean is that is better to have a new jdbc driver connecting to an older
postgresqlinstance than the opposite. 
>
>
>To clarify your points, PostgreSQL knows nothing about Java or JDBC, the PgJDBC driver is a pure Java driver that
implementsthe native protocol of PostgreSQL, so PgJDBC "talks" in the PostgreSQL native language (the binary or text
protocolthat postgres understand). So when a new version of PostgreSQL comes out, the driver has to "understand" the
newor changed stuff so an older version of the driver do not recognize the changed stuff and there might hit a
compatibilityissue. 
>
>
>And as John said, Java 5 is obsolete, my recomendation is to try upgrading the Java version, at least to Java 6, Java
isfor the most part backward compatible, so you can use a new Java Runtime for a Java 5 compiled app. 
>
>
>Then try to update the PgJDBC driver to the latest version, and finally try to upgrade the PostgreSQL server to a
supportedversion. 
>
>
>As always, test, test and do more test for any potential problem.
>
> 
>
>>Best regards,
>>itoshun
>>
>
>

John R Pierce schrieb am 17.01.2017 um 01:28:
>>        Versions of jdbc driver that supported Java 5 can't connect to postgresql 9.4 or later
>>        because
>>         - the versions of jdbc driver don't support JDBC 4, 41 and 42
>>         - the versions of postreqsql don't support JDBC3
>
> java 5 is obsolete and no longer supported, so the postgres jdbc driver no longer goes to the extra effort of testing
tosupport it. 

And so are Java 6 and 7 btw.

John R Pierce schrieb am 17.01.2017 um 01:28:
>>        Versions of jdbc driver that supported Java 5 can't connect to postgresql 9.4 or later
>>        because
>>         - the versions of jdbc driver don't support JDBC 4, 41 and 42
>>         - the versions of postreqsql don't support JDBC3
>
> java 5 is obsolete and no longer supported, so the postgres jdbc driver no longer goes to the extra effort of testing
tosupport it. 

And so are Java 6 and 7 btw.