jakarta.el.ELException: The class [...] must be public, in an exported package, non-abstract and not an interface

[volosied]

Describe the bug
An ELException occurs when a JSP imports static field from an interface.

jakarta.el.ELException: The class [io.openliberty.pages31.fat.misc.other.SomeInterface] must be public, in an exported package, non-abstract and not an interface
at jakarta.el.ImportHandler.findClass(ImportHandler.java:463)
at jakarta.el.ImportHandler.importStatic(ImportHandler.java:297)
at org.apache.jasper.runtime.PageContextImpl.addImportsToELContext(PageContextImpl.java:856)
at [internal classes]
at com.ibm._jsp._staticImportInterface._jspService(_staticImportInterface.java:125)
at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:102)
at [internal classes]`

Steps to Reproduce
A JSP using the pages 3.1 feature imports a static field via an interface.
For example:
<%@ page import = "static io.openliberty.pages31.fat.misc.other.SomeInterface.DEFAULT" %>

Expected behavior
No errors should occur.

Diagnostic information:

• OpenLiberty Version: Since 23.0.0.3
• Affected feature(s) pages-3.1
• Java Version: N/A
• server.xml configuration - N/A

Additional context
Also reported in Tomcat: https://bz.apache.org/bugzilla/show_bug.cgi?id=66582

[volosied]

I'm not too sure about this one and the the specification could be more explicit about interfaces ( mostly because docs just says "static field". The closest text I found is the restrictions section: a class has to be explicitly imported before its static fields or methods can be referenced..

Looking over https://jakarta.ee/specifications/platform/10/apidocs/jakarta/el/package-summary (specifically the ImportHandler - Handles imports of class names and package names.)

importStatic​:

Import a static field or method.

Parameters:
    name - The static member name, including the full class name, to be imported

https://jakarta.ee/specifications/expression-language/5.0/jakarta-expression-language-spec-5.0#imports-of-packages-classes-and-static-fields

Package description mentions concrete classes specially:
Importing a package imports all the public, concrete classes in the package.

Access restrictions:

For security, the following restrictions are enforced.

    Only the public static fields and methods can be referenced.

    Static fields cannot be modified.

    Except for classes with java.lang.* package names, a class has to be explicitly imported before its static fields or methods can be referenced.

There's also the StaticFieldELResolver, but I think the class has to be imported first to be found.

I don't think the EL is meant to handle this situation where a static field from an interface is imported. This also applies to abstract classes (as the error indicates) I think this also explains why the en masse import also fails: #24182

It seems like it could handle this situation though, but it would need to be fixed via the API. It is possible to the field: for example:

                          public interface Test {
	                          public static String DOG = "bark";
                          }

			ClassLoader cl = Thread.currentThread().getContextClassLoader();

			System.out.println(cl.loadClass("Test").getField("DOG").get(null));		

However, I don't see much use for this scenario. If no one has asked for this then it's probably not worth pursuing.

[volosied]

Assigning to @chungngoops

Edit: Name doesn't show up here?