Thread: BUG #7577: JDBC Driver - Compiled with Java 7

The following bug has been logged on the website:

Bug reference:      7577
Logged by:          Nic Willemse
Email address:      nicwillemse@gmail.com
PostgreSQL version: 9.1.0
Operating system:   Linux
Description:        =


Hi, =


I downloaded the JDBC driver located at
http://jdbc.postgresql.org/index.html

I specifically requested the JDBC3 version as Im running Java version 6.

I found that it was compiled using Java 7.

I believe that this should be fixed as JDBC3 is supported by java 5 & 6 and
it would make more sense to have it compiled to this version.

Regards,
Nic

To add to this, it's not just a question of making more sense.  Compiling the
code with Java 7 means the generated class files are version 51, which is
not acceptable to a Java 5 JRE - it wants version 49.  So the existing
pre-built jar cannot simply be dropped into a Java 5 app.

To get around this I'm trying to build from source without much more
success.  When I follow the recommendation of using a 1.5 JDK, for some
reason ant still craps out with an UnsupportedClassVersionError.  I also
tried to hack the build.xml to force compilation with source="1.5" and
target="1.5", but then the compilation fails like this:

compile:
    [javac] /opt/sean/software/postgresql-jdbc-9.0-802.src/build.xml:120:
warning: 'includeantruntime' was not set, defaulting to
build.sysclasspath=last; set to false for repeatable builds
    [javac] Compiling 176 source files to
/opt/sean/software/postgresql-jdbc-9.0-802.src/build
    [javac] warning: [options] bootstrap class path not set in conjunction
with -source 1.5
    [javac]
/opt/sean/software/postgresql-jdbc-9.0-802.src/org/postgresql/Driver.java:47:
error: org.postgresql.Driver is not abstract and does not override abstract
method getParentLogger() in java.sql.Driver
    [javac] public class Driver implements java.sql.Driver
    [javac]        ^
    [javac]
/opt/sean/software/postgresql-jdbc-9.0-802.src/org/postgresql/ds/PGConnectionPoolDataSource.java:39:
error: PGConnectionPoolDataSource is not abstract and does not override
abstract method getParentLogger() in CommonDataSource
    [javac] public class PGConnectionPoolDataSource extends BaseDataSource
implements Serializable, ConnectionPoolDataSource
    [javac]        ^
    [javac]
/opt/sean/software/postgresql-jdbc-9.0-802.src/org/postgresql/ds/PGPooledConnection.java:26:
error: PGPooledConnection is not abstract and does not override abstract
method removeStatementEventListener(StatementEventListener) in
PooledConnection

etc.

Does anyone have a solution for people like me who must use Java 5?

Thanks,
Sean



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On 10/15/2012 11:10 PM, seancompusult wrote:
> Does anyone have a solution for people like me who must use Java 5?

I had no problems building current git head of the JDBC driver with Java
SE 5, nor the REL_9_2_STABLE branch.


export PATH=$HOME/java/jdk1.5.0_22/bin:$HOME/java/jdk1.5.0_22/jre/bin:$PATH;

export JAVA_HOME=$HOME/java/jdk1.5.0_22/

ant clean jar

--
Craig Ringer

On 12-10-16 12:08 AM, Craig Ringer wrote:
> On 10/15/2012 11:10 PM, seancompusult wrote:
>> Does anyone have a solution for people like me who must use Java 5?
>
> I had no problems building current git head of the JDBC driver with
> Java SE 5, nor the REL_9_2_STABLE branch.
>

Ah, quite right.  I was having a problem running ant, because it itself
was compiled with Java 7.  :-(  IMO the whole approach of relying on
compiling with specific Java versions is flawed, but at least I've
gotten past this issue so I'm happy.  Thanks for that.

Sean

On 10/16/2012 08:10 PM, Sean Hogan wrote:
> On 12-10-16 12:08 AM, Craig Ringer wrote:
>> On 10/15/2012 11:10 PM, seancompusult wrote:
>>> Does anyone have a solution for people like me who must use Java 5?
>>
>> I had no problems building current git head of the JDBC driver with
>> Java SE 5, nor the REL_9_2_STABLE branch.
>>
>
> Ah, quite right.  I was having a problem running ant, because it itself
> was compiled with Java 7.  :-(  IMO the whole approach of relying on
> compiling with specific Java versions is flawed, but at least I've
> gotten past this issue so I'm happy.  Thanks for that.

Yes, it's flawed, but it's also unfortunately necessary.

javac offers flags like -source 1.5 -target 1.5 for controlling bytecode
generation and source compatibility. That's fine, but it offers
absolutely no way to say "treat standard library packages, classes and
methods added after Java SE 5 as missing".

This means that for testing at least it's required to build with a
variety of JDK versions.

I agree that it'd be nice to support downlevel class generation for end
users. It may even be possible; I haven't dug into build.xml in detail yet.

--
Craig Ringer