In JspInitializationListener there is a comment saying

if the servlet version is 3.1 or higher, setup a ELResolver which allows usage of static fields java.lang.*

However the conditional following the comment is not testing for "3.1 or higher":

if (servletContext.getEffectiveMajorVersion() >= 3 && servletContext.getEffectiveMinorVersion() >= 1) {

note that e.g. for 4.0 the expression is false

To include 4.0, the expression should be something like

if (servletContext.getEffectiveMajorVersion() > 3 || (servletContext.getEffectiveMajorVersion() == 3 && servletContext.getEffectiveMinorVersion() >= 1)) {

[1] https://github.com/wildfly/wildfly/blob/e8724d5e539ac26b402a5ad10ef3d98839c7497c/undertow/src/main/java/org/wildfly/extension/undertow/deployment/JspInitializationListener.java#L50