Hi,
as Java 11/13 is not yet officially supported by webMethods you will most probably not be able to use such APIs.
You should ask your partner to continue to send you the APIs compiled with Java 8.
Additionally you should consider updating your jvm to build 212 which is t he last publicly available build from Oracle.
Check for the Java Package Fix for your installation to switch to Azul Zulu JVM 8 instead of Oracle.
Reagrds,
Holger
#webMethods#Integration-Server-and-ESB