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From Daniel John Debrunner <...@apache.org>
Subject Re: [jira] Commented: (DERBY-1651) Develop a mechanism to migrate mySQL databases to Derby. Migration tool should include both schema and data migration options.
Date Mon, 21 Aug 2006 18:39:24 GMT
Andrew McIntyre wrote:

> On 8/21/06, Daniel John Debrunner <djd@apache.org> wrote:
> 
>>
>> That is actually engine code, so should not be used by the tools (or the
>> tests)
> 
> 
> Yet there are references to JVMInfo in both ij and sysinfo. Should
> these be removed, then?

Or the code moved into the common area (and bring up that whole can of
worms :-)

> 
>> it would work for some cases (assuming the code was moved), but
>> it doesn't handle J2ME/CDC/Foundation or J2ME/CLDC or Java Card.
> 
> 
> Currently the code in JVMInfo assumes that a J2ME VM is 1.3 level, so
> the code above would currently print an error and exit on those
> platforms, would it not?

No idea, might get a class not found error in starting up. As you say
"assumes" is the key point, it assumes it's running in J2SE (or
J2ME/CDC/Foundation). It doesn't cater to the fact it might be running
in a less enabled environment so it may or may not handle that case. For
example, if Derby ran against OSGi ee.minimum I'm pretty sure it
wouldn't work and it wouldn't get a nice error message, since our error
message handling relies on classes not in OSGi ee.minimum.

Should someone fix that so that Derby produces a nice error message in
OSGi ee.minimum (or CLDC or JavaCard etc.) ? I don't see it as a
requirement.

If someone submitted a patch that made it produce a nice error message
in OSGi ee.minimum then maybe it would be committed, depends on how much
cruft code would be needed to add very little value.

In addition, the JDK_ID level produced by JVMInfo class is just designed
for J2SE and it's Derby's interpretation, not any standard Java concept.
Thus with:

JVMInfo.JDK_ID < JVMInfo.J2SE_15

who knows what JVMInfo.JDK_ID would end up being on J2ME/CLDC or
JavaCard, may end up being a value greater than JVMInfo.J2SE_15.

Dan.




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