Re: Migration to Maven

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. Java.time was also introduced in Java 8.

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.

Mark
--
Mark Rotteveel