Just compile a JRE 8 class down to byte code level 6 and load it on Java level 7. That's what I proposed. Nothing else. It really bet will work unless you try to INSTANTIATE JRE-only classes, but it should LOAD. And nothing more we need.
From: davecramer@gmail.com [mailto:davecramer@gmail.com] On Behalf Of Dave Cramer Sent: Dienstag, 16. Juni 2015 00:54 To: Vladimir Sitnikov Cc: Markus KARG; List Subject: Re: [JDBC] Pre-processing during build
I'm wondering if we use the latest JRE to compile but target 1.7 will it use the latest JDBC API, but compile to 1.7 bytecode. Apparently https://github.com/brettwooldridge/HikariCP uses this method; and they have a similar problem
>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
