I have tested WSO2 AM 1.10.0 in Linux with OpenJDK 1.7. It seems to be working fine, so far.
However, all WSO2 product's documentations say OpenJDK is not supported? Why and what could happen if we put this in PRODUCTION? Should we be concerned?
We prefer OpenJDK so wanted to use it if possible as our other products are also running on top of it.
As Amila mentioned, we faced some issues, mainly related with threading and garbage collections issues with OpenJDK. The gap between the Oracle JDK we support and OpenJDK has considerably been reduced with JDK8. However, all our QA is done with OracleJDK, which is why we say we will not support any other JDK in production. You can run with OpenJDK if you want, but if you encounter an issue and want to report it, you will need to reproduce the same error with Oracle JDK. Note that with the next generation of the WSO2 platform (Carbon 5) we will test both OpenJDK and OracleJDK and therefore both will be officially supported.