Subclass of Camel DefaultContext in version 3.22.3 throws NPE as HeadersMapFactory is not initialized

Migrated existing Camel libraries version 2.25.4 in JBoss EAP 7.4 applications to Camel version 3.22.3. These applications use a subclass of DefaultCamelContext, which work fine in Camel 2.x, but throw a NPE in Camel 3.22.3 as HeadersMapFactory member is null. Explicitly adding setHeadersMapFactory(new DefaultHeadersMapFactory()) fixes the issue.

Would like to know why this step is needed?