Re: Pre-processing during build

Marcus,

>Has anybody tried whether it is possible to simply load a JRE8-JDBC42.jar on JRE6?

As you are a fan of JEPs, you might know of
http://openjdk.java.net/jeps/238 : Multi-Version JAR Files
It does not "just work" yet.

Suppose you want implement PreparedStatement(...java.sql.SQLType)
features of JDBC 4.2 (see [1]).
Even if you compile that with target 1.7, JRE 7 might fail to load the
class as it won't be able to validate what that SQLType is. It just
does not exist in JRE7.

As far as I understand, the only manageable way of using "new
features" in "JDK6-7 jars" is to isolate JDK8-using methods to
JDK8-only-loaded classes. For instance, PreparedStatement41.java and
PreparedStatement42.java

[1]: https://docs.oracle.com/javase/8/docs/api/java/sql/PreparedStatement.html#setObject-int-java.lang.Object-java.sql.SQLType-

Vladimir