KB-1535 Header count exceeded allowed maximum [128]

Symptoms

When users try to access alerts or process details for a process instance in /designer, they may run into an error in the UI like the following:

Users will also see the following error in the JBoss server.log:

java.lang.IllegalStateException: JBWEB002005: Header count exceeded allowed maximum [128]

Cause

The JBoss container limits the Mime Header count to 128 by default. This header count is related to how resources in the /designer interface are accessed.

Workaround

To resolve the issue, perform the following:

1. Stop the application server.
2. Navigate to <JBOSS_HOME>/standalone/configuration/standalone.xml.
3. Inside the standalone.xml file, locate the following: <system-properties><property name="org.apache.tomcat.util.http.Parameters.MAX_COUNT" value="5000"/></system-properties>.
4. Add the following property to the <system-properties> section: <property name="org.apache.tomcat.util.http.MimeHeaders.MAX_COUNT" value="512"/>. This increases the Mime Header count from the default 128 to 512.
5. Save the file and start the application server.

Affected Versions

This article applies to all versions of Appian using JBoss EAP 6.4.x as an application server.

Last Reviewed: April 2018