Re: Migration to Maven

On 26 November 2015 at 13:34, Mark Rotteveel <mark(at)lawinegevaar(dot)nl> wrote:

> On 26-11-2015 18:03, Adam Brightwell wrote:
> >> Our bigger problem is to figure out how to have JDK 1.6, 1.7, and 1.8
> and
> >> ... all supported by one codebase
> >
> > Isn't that what the '-source' and '-target' flags for javac are meant
> > to help solve?
>
> That only helps if you are compiling the same software for different Java
> versions (and then it would suffice to just target Java 6, as Java 6
> bytecode can also be run on newer Java versions).
>
> Also, if you use any new feature in the API, then compiling this way will
> lead to a false sense of security as a Java 7 compiler set to -source and
> -target 1.6 will **not** detect that you used new classes or methods
> (unless you explicitly specify a bootclasspath that points to the Java 6
> runtime classes).
>
> The main problem however is that Java 6 is JDBC 4.0, Java 7 JDBC 4.1 and
> Java 8 JDBC 4.2. Each new version added new methods and requirements. If I
> recall correctly it should be possible to compile JDBC 4.1 compliant code
> with Java 6 (there might be some edge cases), however JDBC 4.2 added a
> number of new methods that take the SQLType interface, which was added in
> Java 8. On top of that, JDBC 4.2 compliance requires implementation of
> java.time support on get/setObject in PreparedStatement and ResultSet.

this is the real problem, thanks for the reminder.

> Java.time was also introduced in Java 8.
>

new methods would be OK, as older JDBC versions would never call them, but
the import for Java.time fails

>
> This makes it impossible to compile the same code for Java 6 and Java 8.
> You need to do some form of preprocessing, or selecting/combining version
> dependent sourcetrees.

Yup

Dave Cramer

davec(at)postgresintl(dot)com
www.postgresintl.com

>
>
> Mark
> --
> Mark Rotteveel
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