[javaee-spec users] [jsr366-experts] Re: default resources

From: Bill Shannon <>
Date: Tue, 11 Nov 2014 12:36:52 -0800

I'd still like to get feedback on this from the rest of you!

Come on, experts, I'm sure you're capable of forming an opinion on this!

Bill Shannon wrote on 11/05/14 16:06:
> Here's a small issue to get the expert group started!...
> There are several places in Java EE 7 where we defined that unmapped
> resources must be mapped to the platform default resources. For example,
> if you define a DataSource resource or a JMS connection factory resource,
> but it's not mapped to a specific (portable or platform-specific)
> resource, it must be automatically mapped at deployment time to the
> corresponding platform default resource.
> See EE.5.19, EE.5.20, and EE.5.21.
> Previously, the expectation was that unmapped resources would result in
> an error at deployment time. The newly defined behavior fails to consider
> two cases:
> 1. The resource might be mapped using a product-specific deployment descriptor.
> The intent was that the default mapping would only occur in the absence
> of any explicit mapping. The spec will need to make this clear.
> 2. The resource might be mapped using a product-specific implicit mapping rule.
> This case is more problematic. With nothing in the application code, and
> nothing in the deployment descriptors, I would normally expect the deployment
> to fail. Some products may have mapped any unmapped resources to some
> administrator-defined product-specific resource using some undefined
> name mangling or defaulting rules. With the Java EE 7 mapping rules, the
> mapping of such resources might change.
> How should we handle case #2?
> A. The product redefined an error case to be a non-error case, which
> conflicts with the Java EE 7 spec. The product has to change.
> B. The spec should allow a product-specific switch that controls whether
> the behavior follows the Java EE 7 rules or the product-specific rules.
> The switch might be per-application or global, but the default must be
> to follow the Java EE 7 rules.
> C. The spec should define a per-application switch to control whether
> unmapped resources are mapped to the platform default resources or
> are handled in a product-specific way. The default behavior would
> be as specified in Java EE 7. This allows applications that depended
> on the old product-specific behavior to continue to work, but only if
> the application is changed.
> D. The spec should allow a resource with no explicit mapping to be
> mapped to an existing product-specific resource using a product-specific
> implicit mapping as long as that product-specific resource exists. If
> the product-specific resource does not exist, the resource must be mapped
> to the platform-defined default resource. This somewhat reduces
> portability while providing some compatibility with existing products
> that use implicit mapping rules.
> Note that parts of B, C, and D could all be done; these choices need not
> be exclusive.
> Please let me know what you think.
> Thanks.