Saturday, February 2, 2019

Re: upgrade gwt 2.7 to gwt 2.8.1 not working

On Friday, February 1, 2019 at 10:31:01 PM UTC+1, Thad Humphries wrote:
Thanks! You answered this question over a year and a half ago, but I just hit this very problem while converting an app from 2.7.0 to 2.8.2. (Why now? With Oracle cutting off Java 8, we moved to Amazon Corretto, and found some old imaging stuff that would not work with OpenJDK. As long as I was correcting this and moving from Java 6 to OpenJDK 8--and with this weeks Canary problems in mind--I decided to bump GWT as well.)

Interesting what you say about Jetty in 2.7.0: I've never had a problem with Servlet spec 2.5 and GWT 2.7.0 (this app has used 2.5 for years). 

From my testing with Tomcat 8.5, I can still use servlet 2.5 or 3.0 in the web.xml header of the deployed app. Have you seen issues in deployment? I ask because we've one customer who runs WebLogic and their current version-- supports up to 3.0.

This was a classpath issue, not a webapp one. You never package the servlet APIs in your WARs, and even if you did, the server would use its own version and ignore yours. So as long as you don't use newer APIs that the target server doesn't support, you're safe.
The problem is if you put an older API in the server's classpath (in the case of GWT, the devmode classpath), like if you shadowed/replaced WebLogic's own servlet API with another one.
Fwiw, separating client and server code into separate "modules" (separate classpaths: only including client-side dependencies in the devmode classpath, leaving server-side dependencies to the webapp's WEB-INF/lib), something I've been advocating for years, generally solves these conflicts.

You received this message because you are subscribed to the Google Groups "GWT Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to
To post to this group, send email to
Visit this group at
For more options, visit

No comments:

Post a Comment