[jboss-jira] [Red Hat JIRA] (WFLY-13924) HTTP2 is not working with Oracle JDK8 u261

HTTP2 is not working with Oracle JDK8 u261 ------------------------------------------ Key: WFLY-13924 URL: https://issues.redhat.com/browse/WFLY-13924 Project: WildFly Issue Type: Bug Components: Security, Web (Undertow) Affects Versions: 20.0.0.Final, 20.0.1.Final, 21.0.0.Beta1 Reporter: Jan Stourac Assignee: Flavia Rainone Priority: Blocker Fix For: 21.0.0.Final There seems to be some problem with HTTP2 support with new Oracle JDK8 u261 and WildFly since {{20.0.0.Final}} version. When request against server is executed, then HTTP2 is not established and communication remains via HTTP/1.1. There is no such issue when I use {{WildFly 19.0.0.Final}}. Also, if I switch back to an older Oracle JDK8 u241, there is no such issue even with newer WildFly versions. This all seems to be tied with backport of ALPN support into the Oracle JDK8 recently and also work in following issue UNDERTOW-1726. There seems to be a workaround available - to define '-Dio.undertow.protocols.alpn.jdk8' during the server startup. With this property configured, the issue seems to disappear (as such, blocker priority of this may be discussed). *What is the issue here:* This is a change in default behavior of the server (HTTP2 not working with Oracle JDK8u261+ since WildFly 20.0.0.Final). We should try to resolve this without default behavior change if possible. Only in case there is really no other solution, we need to document such thing.