You don't really need the gwtar support with PersistentUnitCaching enabled,
which it should be by default. The performance of the persistent unit cache
is usually as good or better, and the mechanism in play is pretty much the
same, only you don' t have to configure anything special to use the
persistent unit cache. The purpose of the pre-compiled archives (.gwtar
files) is to distribute them with a versioned GWT distribution for users
that aren't building from source.
If you are routinely building and updating the GWT distribution, you need to
make sure to re-compile the modules every time you update the GWT
distribution. There are so many things that could change, we don't plan to
try to offer backward compatibility guarantees with these files.
On Sat, Jun 18, 2011 at 2:14 PM, Stephen Haberman <
stephen.haber...@gmail.com <{subItem.from.uri}>> wrote:
> Hey,
>
> I'm debugging a GWT app while using the trunk Eclipse gwt-dev/gwt-user
> projects (so I can make changes to GWT and then start my app without
> rebuilding the gwt-user/gwt-dev jar files with ant).
>
> It turns out that, with this setup, I can't take advantage of the
> new gwtar functionality because of serialVersionUID mismatches.
>
> User.gwtar is built with ant+javac using javac's .class files, but when
> I run the app in Eclipse, using the Eclipse gwt-dev project's .class
> files, deserialization of the gwtar fails because Eclipse and javac
> generate different serialVersionUIDs, even if the source file is
> exactly the same:
>
>
> http://wiki.eclipse.org/FAQ_Why_does_the_Eclipse_compiler_create_a_different_serialVersionUID_from_javac%3F<http://www.google.com/url?sa=D&q=http://wiki.eclipse.org/FAQ_Why_does_the_Eclipse_compiler_create_a_different_serialVersionUID_from_javac%253F>
>
> So I don't get the fancy new gwtar startup times. Which I miss.
>
> Granted, most of the time .gwtar files will be generated in the same
> build cycle as their .class files. And, granted, there are a whole
> bunch of classes that are being serialized.
>
> Hm...although, let's say I build my-library.gwtar with GWT x.y, so
> JDeclaredType/whatever has serialVersionUID=z. If a new release of GWT
> comes out, GWT x.y+1, the serialVersionUID might change unnecessarily
> (per the FAQ, due to a javac implementation change) and be z', causing
> my-library.gwtar to be unusable to projects using GWT x.y+1.
>
> Granted, recompiling my-library.gwtar would fix it. And, at times, would
> actually be necessary if the serialVersionUID changed not arbitrarily
> but due to a format change. So perhaps this isn't a big deal.
>
> Anyway, I thought I'd ask, are there any plans to add serialVersionUIDs?
>
> - Stephen
>
>
> --
> http://groups.google.com/group/Google-Web-Toolkit-Contributors
>
--
http://groups.google.com/group/Google-Web-Toolkit-Contributors
