Hi Julo,
The Java 5 compiler lets us write product and test code which is
optional--that is, the code only runs if the VM is sufficiently
advanced. This has the following benefits:
1) For runtime-optional code, we can take advantage of optimizations
introduced by the Java 5 libraries.
2) For runtime-optional code, we can take advantage of the extra type
checking introduced by Java 5.
3) We can write runtime-optional tests which verify that Derby plays
well with customer-written code on advanced VMs.
The net effect of 1-3 is better Derby performance and quality when run
on advanced VMs. In addition,
4) It moves us further toward a standard build environment. That, in the
long run, will improve the out-of-box experience for newcomers to
derby-dev. It also reduces the release-time thrashing caused by the fact
that the release manager's environment is so different from the
environment of the average developer.
5) It moves more of the onus of build failures onto the developers who
make the build-breaking changes.
The net effect of 4-5 is reduced thrashing during development and release.
Hope this helps,
-Rick
Julius Stroffek wrote:
Hi Rick,
I am just thinking what exact benefits will derby gain when using java
5 features.
Both Java 1.4 and Java 1.5 use JDBC3 interface and therefore I would
expect derby to behave the same way on both java versions. Is this
supposed somehow to change? Which derby features would be affected by
this? Any plans for near future?
Thanks
Julo
Rick Hillegas wrote:
Rick Hillegas wrote:
I would like to start writing Derby code which makes use of Java 5
features. More specifically:
1) I would like to take advantage of the Java 5 extensions for
ease-of-use and stronger type checking.
2) I would like to be able to write regression tests which verify
that user-written Java 5 code runs correctly as Derby functions and
procedures.
Would anyone object to our requiring that developers use a Java 5 or
later compiler to build Derby? I believe that we would still require
the presence of the 1.4 libraries and the expectation would continue
to be that the compiler must compile down to 1.4 classes.
Thanks,
-Rick
Discussion on this thread has died down so I would like to summarize
what has been said so far:
a) Java 5 source can't be compiled down to 1.4 class files. This
means that any code which is necessary for Derby to operate must be
1.4 source. This means that mandatory code cannot take advantage of
Java 5 features such as enums, generics, annotations, and varargs.
b) The CDC small device platforms require 1.4 level class files. Java
5 class files will not run on CDC platforms.
c) There is no problem with using the Java 5 compiler to compile 1.4
source into 1.4 targets. This already works today for those of us
whose default compiler is Java 5 or Java 6.
d) Java 5 is available on all likely development platforms, including
Windows, Linux, Mac OS X, and Solaris.
e) If we required Java 5 (or higher) in order to compile Derby, then
we could use Java 5 features in optional engine code and in optional
tests.
I propose that we require Java 5 (or higher) in order to build Derby.
If there are no objections and no further discussion, then I intend
to call a lazy consensus vote on this proposal.
Regards,
-Rick
