When in web application there are several tag libraries packed in jar files that have tag files in them, when those files are compiled they share the same package: org.apache.jsp.tag.meta As a result, if there are tags with the same name in different libraries, only one of them survives. I encountered it while investigating bug #37084. See comment #13 there.
Created attachment 23083 [details] webapp that reproduces the issue To reproduce: 1. Deploy the web application 2. Access http://localhost:8080/bug46471/ 3. The page emits some text/plain text Expected result: tag from mylibA tag from mylibB Actual result: tag from mylibB tag from mylibB 4. Check the generated files in the work folder. It is expected to have one jsp page and three tags been generated (one from the WEB-INF/tags and two from the different tag libs), but only two tags are generated. Reproduced in the current tc6.0.x, but I expect it to also be in TC 6.0.18.
I have fixed this in trunk and proposed the patch for 6.0.x. The patch is fairly invasive so there may be some reluctance to back port this to 6.0.x (although all the TCK tests do pass).
This has been fixed in 6.0.x and will be in 6.0.19 onwards.