Wildfly 8.1.0.Final has a bug in the undertow-1.0.15.Final module--this contains a one-liner command to perform a patch
The bug is described in detail in this stackoverflow article
The problem is a NullPointerException here:
at io.undertow.servlet.spec.HttpServletResponseImpl.getHeaders(HttpServletResponseImpl.java:248) [undertow-servlet-1.0.15.Final.jar:1.0.15.Final]
where the code (line 248) causing the NPE is:
@Override
public Collection<String> getHeaders(final String name) {
return new ArrayList<String>(exchange.getResponseHeaders().get(name));
}
The diff of the fix patch is :
46d45
< import io.undertow.util.HeaderValues;
249,253c248
< final HeaderValues headerValues = exchange.getResponseHeaders().get(name);
< if (headerValues != null) {
< return new ArrayList<String>(headerValues);
< }
< return new ArrayList<String>();
---
> return new ArrayList<String>(exchange.getResponseHeaders().get(name));
You can patch your existing WF 8.1.0.Final installation with a simple bash shell script if you don't want to (or can't) upgrade your WF installation to > 8.2.*, which doesnt have this bug.
The script will make a backup of your current $WILDFLY_HOME/modules/system/layers/base/io/undertow/servlet/main/undertow-servlet-1.0.15.Final.jar file, and replace it with the patched $WILDFLY_HOME/modules/system/layers/base/io/undertow/servlet/main/undertow-servlet-1.0.15.Final.jar
The backup will be named $WILDFLY_HOME/modules/system/layers/base/io/undertow/servlet/main/undertow-servlet-1.0.15.Final.jar.backup
###Run this to patch:
export WILDFLY_HOME=[path to your wildfly 8.1.0.Final installation]
curl https://raw.githubusercontent.com/ldojo/wf-8.1.0-undertow-1.0.15-patch/master/wf-8.1.0-undertow-1.0.15-patch.sh | bash